From ed02344fbc7d3bed591f528304f603f9d320e919 Mon Sep 17 00:00:00 2001
From: Andrew Cann <shum@canndrew.org>
Date: Sun, 31 Jul 2016 22:33:41 +0800
Subject: [PATCH] Remove obsolete divergence related stuff

Replace FnOutput with Ty
Replace FnConverging(ty) with ty
Purge FnDiverging, FunctionRetTy::NoReturn and FunctionRetTy::None
---
 src/librustc/cfg/construct.rs                 |   2 +-
 src/librustc/hir/fold.rs                      |   1 -
 src/librustc/hir/lowering.rs                  |   1 -
 src/librustc/hir/mod.rs                       |   4 -
 src/librustc/hir/print.rs                     |   5 -
 src/librustc/infer/error_reporting.rs         |   1 -
 src/librustc/infer/mod.rs                     |   1 -
 src/librustc/middle/intrinsicck.rs            |   7 +-
 src/librustc/middle/liveness.rs               |  83 ++++++------
 src/librustc/middle/mem_categorization.rs     |   3 +-
 src/librustc/mir/repr.rs                      |   6 +-
 src/librustc/mir/tcx.rs                       |   2 +-
 src/librustc/mir/visit.rs                     |  23 +---
 src/librustc/traits/object_safety.rs          |   6 +-
 src/librustc/traits/select.rs                 |   4 +-
 src/librustc/traits/util.rs                   |   2 +-
 src/librustc/ty/adjustment.rs                 |   3 +-
 src/librustc/ty/flags.rs                      |   5 +-
 src/librustc/ty/fold.rs                       |   6 -
 src/librustc/ty/mod.rs                        |   3 +-
 src/librustc/ty/relate.rs                     |  17 +--
 src/librustc/ty/structural_impls.rs           |  32 -----
 src/librustc/ty/sty.rs                        |  51 +-------
 src/librustc/ty/walk.rs                       |   5 +-
 src/librustc/util/ppaux.rs                    |  19 +--
 .../borrowck/mir/gather_moves.rs              |  23 ++--
 src/librustc_driver/test.rs                   |   2 +-
 src/librustc_lint/builtin.rs                  |   7 +-
 src/librustc_lint/types.rs                    |  17 +--
 src/librustc_metadata/tydecode.rs             |   8 +-
 src/librustc_metadata/tyencode.rs             |   9 +-
 src/librustc_mir/build/expr/into.rs           |   2 +-
 src/librustc_mir/build/mod.rs                 |  14 +-
 src/librustc_mir/graphviz.rs                  |  11 +-
 src/librustc_mir/hair/cx/expr.rs              |  10 +-
 src/librustc_mir/pretty.rs                    |  12 +-
 src/librustc_mir/transform/promote_consts.rs  |   6 +-
 src/librustc_mir/transform/qualify_consts.rs  |   4 +-
 src/librustc_mir/transform/type_check.rs      |  33 ++---
 src/librustc_privacy/lib.rs                   |   2 +-
 src/librustc_save_analysis/lib.rs             |   1 -
 src/librustc_trans/abi.rs                     |   7 +-
 src/librustc_trans/base.rs                    |   4 +-
 src/librustc_trans/callee.rs                  |  13 +-
 src/librustc_trans/closure.rs                 |   6 +-
 src/librustc_trans/common.rs                  |   6 +-
 src/librustc_trans/debuginfo/metadata.rs      |  33 +----
 src/librustc_trans/debuginfo/mod.rs           |  12 +-
 src/librustc_trans/debuginfo/type_names.rs    |  12 +-
 src/librustc_trans/declare.rs                 |   2 +-
 src/librustc_trans/expr.rs                    |   4 +-
 src/librustc_trans/intrinsic.rs               |  13 +-
 src/librustc_trans/mir/analyze.rs             |   3 +-
 src/librustc_trans/mir/block.rs               |   6 +-
 src/librustc_trans/mir/mod.rs                 |   3 +-
 src/librustc_trans/trans_item.rs              |  14 +-
 src/librustc_typeck/astconv.rs                |  14 +-
 src/librustc_typeck/check/callee.rs           |   7 +-
 src/librustc_typeck/check/closure.rs          |   2 +-
 src/librustc_typeck/check/intrinsic.rs        |  14 +-
 src/librustc_typeck/check/mod.rs              | 120 +++++++-----------
 src/librustc_typeck/check/op.rs               |   2 +-
 src/librustc_typeck/check/regionck.rs         |  15 +--
 src/librustc_typeck/check/wfcheck.rs          |  13 +-
 src/librustc_typeck/collect.rs                |  10 +-
 src/librustc_typeck/lib.rs                    |   4 +-
 src/librustc_typeck/variance/constraints.rs   |   4 +-
 src/librustdoc/clean/mod.rs                   |  11 --
 src/librustdoc/html/format.rs                 |   1 -
 src/libsyntax/ast.rs                          |   4 -
 src/libsyntax/fold.rs                         |   1 -
 src/libsyntax/print/pprust.rs                 |   6 -
 src/test/run-pass/issue-10714.rs              |  16 ---
 73 files changed, 249 insertions(+), 586 deletions(-)
 delete mode 100644 src/test/run-pass/issue-10714.rs

diff --git a/src/librustc/cfg/construct.rs b/src/librustc/cfg/construct.rs
index 89964043819..b3f7af77691 100644
--- a/src/librustc/cfg/construct.rs
+++ b/src/librustc/cfg/construct.rs
@@ -379,7 +379,7 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
 
         let func_or_rcvr_exit = self.expr(func_or_rcvr, pred);
         let ret = self.straightline(call_expr, func_or_rcvr_exit, args);
-        if fn_ty.fn_ret().diverges(self.tcx) {
+        if fn_ty.fn_ret().0.is_empty(self.tcx) {
             self.add_unreachable_node()
         } else {
             ret
diff --git a/src/librustc/hir/fold.rs b/src/librustc/hir/fold.rs
index 822a603fbb8..d8b39f1f958 100644
--- a/src/librustc/hir/fold.rs
+++ b/src/librustc/hir/fold.rs
@@ -516,7 +516,6 @@ pub fn noop_fold_fn_decl<T: Folder>(decl: P<FnDecl>, fld: &mut T) -> P<FnDecl> {
             output: match output {
                 Return(ty) => Return(fld.fold_ty(ty)),
                 DefaultReturn(span) => DefaultReturn(span),
-                NoReturn(span) => NoReturn(span),
             },
             variadic: variadic,
         }
diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs
index 3170dd1884a..45eaca4100b 100644
--- a/src/librustc/hir/lowering.rs
+++ b/src/librustc/hir/lowering.rs
@@ -403,7 +403,6 @@ impl<'a> LoweringContext<'a> {
             output: match decl.output {
                 FunctionRetTy::Ty(ref ty) => hir::Return(self.lower_ty(ty)),
                 FunctionRetTy::Default(span) => hir::DefaultReturn(span),
-                FunctionRetTy::None(span) => hir::NoReturn(span),
             },
             variadic: decl.variadic,
         })
diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs
index 366b0100bda..d726625f2fc 100644
--- a/src/librustc/hir/mod.rs
+++ b/src/librustc/hir/mod.rs
@@ -1286,9 +1286,6 @@ impl fmt::Debug for ImplPolarity {
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum FunctionRetTy {
-    /// Functions with return type `!`that always
-    /// raise an error or exit (i.e. never return to the caller)
-    NoReturn(Span),
     /// Return type is not specified.
     ///
     /// Functions default to `()` and
@@ -1302,7 +1299,6 @@ pub enum FunctionRetTy {
 impl FunctionRetTy {
     pub fn span(&self) -> Span {
         match *self {
-            NoReturn(span) => span,
             DefaultReturn(span) => span,
             Return(ref ty) => ty.span,
         }
diff --git a/src/librustc/hir/print.rs b/src/librustc/hir/print.rs
index 71694bc4e7d..20d069c126d 100644
--- a/src/librustc/hir/print.rs
+++ b/src/librustc/hir/print.rs
@@ -1962,10 +1962,6 @@ impl<'a> State<'a> {
                 self.maybe_print_comment(ty.span.lo)
             }
             hir::DefaultReturn(..) => unreachable!(),
-            hir::NoReturn(span) => {
-                self.word_nbsp("!")?;
-                self.maybe_print_comment(span.lo)
-            }
         }
     }
 
@@ -2198,7 +2194,6 @@ impl<'a> State<'a> {
         self.ibox(indent_unit)?;
         self.word_space("->")?;
         match decl.output {
-            hir::NoReturn(_) => self.word_nbsp("!")?,
             hir::DefaultReturn(..) => unreachable!(),
             hir::Return(ref ty) => self.print_type(&ty)?,
         }
diff --git a/src/librustc/infer/error_reporting.rs b/src/librustc/infer/error_reporting.rs
index 3ad5ef1e0ff..b0dec3277a9 100644
--- a/src/librustc/infer/error_reporting.rs
+++ b/src/librustc/infer/error_reporting.rs
@@ -1326,7 +1326,6 @@ impl<'a, 'gcx, 'tcx> Rebuilder<'a, 'gcx, 'tcx> {
                 self.rebuild_arg_ty_or_output(&ret_ty, lifetime, anon_nums, region_names)
             ),
             hir::DefaultReturn(span) => hir::DefaultReturn(span),
-            hir::NoReturn(span) => hir::NoReturn(span)
         }
     }
 
diff --git a/src/librustc/infer/mod.rs b/src/librustc/infer/mod.rs
index 697478015cb..24fadc549fa 100644
--- a/src/librustc/infer/mod.rs
+++ b/src/librustc/infer/mod.rs
@@ -607,7 +607,6 @@ impl_trans_normalize!('gcx,
     Ty<'gcx>,
     &'gcx Substs<'gcx>,
     ty::FnSig<'gcx>,
-    ty::FnOutput<'gcx>,
     &'gcx ty::BareFnTy<'gcx>,
     ty::ClosureSubsts<'gcx>,
     ty::PolyTraitRef<'gcx>
diff --git a/src/librustc/middle/intrinsicck.rs b/src/librustc/middle/intrinsicck.rs
index 15f2f21ef25..a1a4f15b9f7 100644
--- a/src/librustc/middle/intrinsicck.rs
+++ b/src/librustc/middle/intrinsicck.rs
@@ -161,10 +161,9 @@ impl<'a, 'gcx, 'tcx, 'v> Visitor<'v> for ExprVisitor<'a, 'gcx, 'tcx> {
                     let typ = self.infcx.tcx.node_id_to_type(expr.id);
                     match typ.sty {
                         ty::TyFnDef(_, _, ref bare_fn_ty) if bare_fn_ty.abi == RustIntrinsic => {
-                            if let ty::FnConverging(to) = bare_fn_ty.sig.0.output {
-                                let from = bare_fn_ty.sig.0.inputs[0];
-                                self.check_transmute(expr.span, from, to, expr.id);
-                            }
+                            let from = bare_fn_ty.sig.0.inputs[0];
+                            let to = bare_fn_ty.sig.0.output;
+                            self.check_transmute(expr.span, from, to, expr.id);
                         }
                         _ => {
                             span_bug!(expr.span, "transmute wasn't a bare fn?!");
diff --git a/src/librustc/middle/liveness.rs b/src/librustc/middle/liveness.rs
index 3a293c304ee..38988affbd0 100644
--- a/src/librustc/middle/liveness.rs
+++ b/src/librustc/middle/liveness.rs
@@ -1112,7 +1112,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
 
           hir::ExprCall(ref f, ref args) => {
             let diverges = !self.ir.tcx.is_method_call(expr.id) &&
-                self.ir.tcx.expr_ty_adjusted(&f).fn_ret().diverges(self.ir.tcx);
+                self.ir.tcx.expr_ty_adjusted(&f).fn_ret().0.is_empty(self.ir.tcx);
             let succ = if diverges {
                 self.s.exit_ln
             } else {
@@ -1125,7 +1125,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
           hir::ExprMethodCall(_, _, ref args) => {
             let method_call = ty::MethodCall::expr(expr.id);
             let method_ty = self.ir.tcx.tables.borrow().method_map[&method_call].ty;
-            let succ = if method_ty.fn_ret().diverges(self.ir.tcx) {
+            let succ = if method_ty.fn_ret().0.is_empty(self.ir.tcx) {
                 self.s.exit_ln
             } else {
                 succ
@@ -1454,7 +1454,7 @@ fn check_fn(_v: &Liveness,
 }
 
 impl<'a, 'tcx> Liveness<'a, 'tcx> {
-    fn fn_ret(&self, id: NodeId) -> ty::PolyFnOutput<'tcx> {
+    fn fn_ret(&self, id: NodeId) -> ty::Binder<ty::Ty<'tcx>> {
         let fn_ty = self.ir.tcx.node_id_to_type(id);
         match fn_ty.sty {
             ty::TyClosure(closure_def_id, substs) =>
@@ -1477,55 +1477,44 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
                 self.ir.tcx.region_maps.call_site_extent(id, body.id),
                 &self.fn_ret(id));
 
-        match fn_ret {
-            ty::FnConverging(t_ret)
-                    if self.live_on_entry(entry_ln, self.s.no_ret_var).is_some() => {
+        if self.live_on_entry(entry_ln, self.s.no_ret_var).is_some() {
+            let param_env = ParameterEnvironment::for_item(self.ir.tcx, id);
+            let t_ret_subst = fn_ret.subst(self.ir.tcx, &param_env.free_substs);
+            let is_nil = self.ir.tcx.infer_ctxt(None, Some(param_env),
+                                                Reveal::All).enter(|infcx| {
+                let cause = traits::ObligationCause::dummy();
+                traits::fully_normalize(&infcx, cause, &t_ret_subst).unwrap().is_nil()
+            });
 
-                let param_env = ParameterEnvironment::for_item(self.ir.tcx, id);
-                let t_ret_subst = t_ret.subst(self.ir.tcx, &param_env.free_substs);
-                let is_nil = self.ir.tcx.infer_ctxt(None, Some(param_env),
-                                                    Reveal::All).enter(|infcx| {
-                    let cause = traits::ObligationCause::dummy();
-                    traits::fully_normalize(&infcx, cause, &t_ret_subst).unwrap().is_nil()
-                });
-
-                // for nil return types, it is ok to not return a value expl.
-                if !is_nil {
-                    let ends_with_stmt = match body.expr {
-                        None if !body.stmts.is_empty() =>
-                            match body.stmts.last().unwrap().node {
-                                hir::StmtSemi(ref e, _) => {
-                                    self.ir.tcx.expr_ty(&e) == t_ret
-                                },
-                                _ => false
+            // for nil return types, it is ok to not return a value expl.
+            if !is_nil {
+                let ends_with_stmt = match body.expr {
+                    None if !body.stmts.is_empty() =>
+                        match body.stmts.last().unwrap().node {
+                            hir::StmtSemi(ref e, _) => {
+                                self.ir.tcx.expr_ty(&e) == fn_ret
                             },
-                        _ => false
+                            _ => false
+                        },
+                    _ => false
+                };
+                let mut err = struct_span_err!(self.ir.tcx.sess,
+                                               sp,
+                                               E0269,
+                                               "not all control paths return a value");
+                if ends_with_stmt {
+                    let last_stmt = body.stmts.last().unwrap();
+                    let original_span = original_sp(self.ir.tcx.sess.codemap(),
+                                                    last_stmt.span, sp);
+                    let span_semicolon = Span {
+                        lo: original_span.hi - BytePos(1),
+                        hi: original_span.hi,
+                        expn_id: original_span.expn_id
                     };
-                    let mut err = struct_span_err!(self.ir.tcx.sess,
-                                                   sp,
-                                                   E0269,
-                                                   "not all control paths return a value");
-                    if ends_with_stmt {
-                        let last_stmt = body.stmts.last().unwrap();
-                        let original_span = original_sp(self.ir.tcx.sess.codemap(),
-                                                        last_stmt.span, sp);
-                        let span_semicolon = Span {
-                            lo: original_span.hi - BytePos(1),
-                            hi: original_span.hi,
-                            expn_id: original_span.expn_id
-                        };
-                        err.span_help(span_semicolon, "consider removing this semicolon:");
-                    }
-                    err.emit();
+                    err.span_help(span_semicolon, "consider removing this semicolon:");
                 }
+                err.emit();
             }
-            ty::FnDiverging
-                if self.live_on_entry(entry_ln, self.s.clean_exit_var).is_some() => {
-                    span_err!(self.ir.tcx.sess, sp, E0270,
-                        "computation may converge in a function marked as diverging");
-                }
-
-            _ => {}
         }
     }
 
diff --git a/src/librustc/middle/mem_categorization.rs b/src/librustc/middle/mem_categorization.rs
index 9589687cf26..bee17c31248 100644
--- a/src/librustc/middle/mem_categorization.rs
+++ b/src/librustc/middle/mem_categorization.rs
@@ -923,7 +923,7 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
         let base_cmt = match method_ty {
             Some(method_ty) => {
                 let ref_ty =
-                    self.tcx().no_late_bound_regions(&method_ty.fn_ret()).unwrap().unwrap();
+                    self.tcx().no_late_bound_regions(&method_ty.fn_ret()).unwrap();
                 self.cat_rvalue_node(node.id(), node.span(), ref_ty)
             }
             None => base_cmt
@@ -1245,7 +1245,6 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
         // to skip past the binder.
         self.tcx().no_late_bound_regions(&method_ty.fn_ret())
            .unwrap()
-           .unwrap() // overloaded ops do not diverge, either
     }
 }
 
diff --git a/src/librustc/mir/repr.rs b/src/librustc/mir/repr.rs
index 08614ca253b..549026290c9 100644
--- a/src/librustc/mir/repr.rs
+++ b/src/librustc/mir/repr.rs
@@ -17,7 +17,7 @@ use rustc_data_structures::control_flow_graph::{GraphPredecessors, GraphSuccesso
 use rustc_data_structures::control_flow_graph::ControlFlowGraph;
 use hir::def_id::DefId;
 use ty::subst::Substs;
-use ty::{self, AdtDef, ClosureSubsts, FnOutput, Region, Ty};
+use ty::{self, AdtDef, ClosureSubsts, Region, Ty};
 use util::ppaux;
 use rustc_back::slice;
 use hir::InlineAsm;
@@ -74,7 +74,7 @@ pub struct Mir<'tcx> {
     pub promoted: IndexVec<Promoted, Mir<'tcx>>,
 
     /// Return type of the function.
-    pub return_ty: FnOutput<'tcx>,
+    pub return_ty: Ty<'tcx>,
 
     /// Variables: these are stack slots corresponding to user variables. They may be
     /// assigned many times.
@@ -107,7 +107,7 @@ impl<'tcx> Mir<'tcx> {
     pub fn new(basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
                visibility_scopes: IndexVec<VisibilityScope, VisibilityScopeData>,
                promoted: IndexVec<Promoted, Mir<'tcx>>,
-               return_ty: FnOutput<'tcx>,
+               return_ty: Ty<'tcx>,
                var_decls: IndexVec<Var, VarDecl<'tcx>>,
                arg_decls: IndexVec<Arg, ArgDecl<'tcx>>,
                temp_decls: IndexVec<Temp, TempDecl<'tcx>>,
diff --git a/src/librustc/mir/tcx.rs b/src/librustc/mir/tcx.rs
index 534bb2c0b2b..cf91229f1c7 100644
--- a/src/librustc/mir/tcx.rs
+++ b/src/librustc/mir/tcx.rs
@@ -125,7 +125,7 @@ impl<'tcx> Lvalue<'tcx> {
             &Lvalue::Static(def_id) =>
                 LvalueTy::Ty { ty: tcx.lookup_item_type(def_id).ty },
             &Lvalue::ReturnPointer =>
-                LvalueTy::Ty { ty: mir.return_ty.unwrap() },
+                LvalueTy::Ty { ty: mir.return_ty },
             &Lvalue::Projection(ref proj) =>
                 proj.base.ty(mir, tcx).projection_ty(tcx, &proj.elem),
         }
diff --git a/src/librustc/mir/visit.rs b/src/librustc/mir/visit.rs
index d44f00ed2cb..66cdc7f156d 100644
--- a/src/librustc/mir/visit.rs
+++ b/src/librustc/mir/visit.rs
@@ -11,7 +11,7 @@
 use middle::const_val::ConstVal;
 use hir::def_id::DefId;
 use ty::subst::Substs;
-use ty::{ClosureSubsts, FnOutput, Region, Ty};
+use ty::{ClosureSubsts, Region, Ty};
 use mir::repr::*;
 use rustc_const_math::ConstUsize;
 use rustc_data_structures::tuple_slice::TupleSlice;
@@ -38,9 +38,7 @@ use syntax_pos::Span;
 //
 // For the most part, we do not destructure things external to the
 // MIR, e.g. types, spans, etc, but simply visit them and stop. This
-// avoids duplication with other visitors like `TypeFoldable`. But
-// there is one exception: we do destructure the `FnOutput` to reach
-// the type within. Just because.
+// avoids duplication with other visitors like `TypeFoldable`.
 //
 // ## Updating
 //
@@ -192,11 +190,6 @@ macro_rules! make_mir_visitor {
                 self.super_source_info(source_info);
             }
 
-            fn visit_fn_output(&mut self,
-                               fn_output: & $($mutability)* FnOutput<'tcx>) {
-                self.super_fn_output(fn_output);
-            }
-
             fn visit_ty(&mut self,
                         ty: & $($mutability)* Ty<'tcx>) {
                 self.super_ty(ty);
@@ -261,7 +254,7 @@ macro_rules! make_mir_visitor {
                     self.visit_visibility_scope_data(scope);
                 }
 
-                self.visit_fn_output(&$($mutability)* mir.return_ty);
+                self.visit_ty(&$($mutability)* mir.return_ty);
 
                 for var_decl in &$($mutability)* mir.var_decls {
                     self.visit_var_decl(var_decl);
@@ -702,16 +695,6 @@ macro_rules! make_mir_visitor {
                 self.visit_visibility_scope(scope);
             }
 
-            fn super_fn_output(&mut self, fn_output: & $($mutability)* FnOutput<'tcx>) {
-                match *fn_output {
-                    FnOutput::FnConverging(ref $($mutability)* ty) => {
-                        self.visit_ty(ty);
-                    }
-                    FnOutput::FnDiverging => {
-                    }
-                }
-            }
-
             fn super_ty(&mut self, _ty: & $($mutability)* Ty<'tcx>) {
             }
 
diff --git a/src/librustc/traits/object_safety.rs b/src/librustc/traits/object_safety.rs
index 93c6dd09e07..48898958601 100644
--- a/src/librustc/traits/object_safety.rs
+++ b/src/librustc/traits/object_safety.rs
@@ -269,10 +269,8 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                 return Some(MethodViolationCode::ReferencesSelf);
             }
         }
-        if let ty::FnConverging(result_type) = sig.0.output {
-            if self.contains_illegal_self_type_reference(trait_def_id, result_type) {
-                return Some(MethodViolationCode::ReferencesSelf);
-            }
+        if self.contains_illegal_self_type_reference(trait_def_id, sig.0.output) {
+            return Some(MethodViolationCode::ReferencesSelf);
         }
 
         // We can't monomorphize things like `fn foo<A>(...)`.
diff --git a/src/librustc/traits/select.rs b/src/librustc/traits/select.rs
index 131074443b4..d535606d1b6 100644
--- a/src/librustc/traits/select.rs
+++ b/src/librustc/traits/select.rs
@@ -1388,7 +1388,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                 abi: Abi::Rust,
                 sig: ty::Binder(ty::FnSig {
                     inputs: _,
-                    output: ty::FnConverging(_),
+                    output: _,
                     variadic: false
                 })
             }) |
@@ -1397,7 +1397,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                 abi: Abi::Rust,
                 sig: ty::Binder(ty::FnSig {
                     inputs: _,
-                    output: ty::FnConverging(_),
+                    output: _,
                     variadic: false
                 })
             }) => {
diff --git a/src/librustc/traits/util.rs b/src/librustc/traits/util.rs
index a097c0093b2..818eb4eb2fb 100644
--- a/src/librustc/traits/util.rs
+++ b/src/librustc/traits/util.rs
@@ -515,7 +515,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             def_id: fn_trait_def_id,
             substs: self.mk_substs(trait_substs),
         };
-        ty::Binder((trait_ref, sig.0.output.unwrap_or(self.mk_nil())))
+        ty::Binder((trait_ref, sig.0.output))
     }
 }
 
diff --git a/src/librustc/ty/adjustment.rs b/src/librustc/ty/adjustment.rs
index 95b3a8bd42e..1bb92d6356c 100644
--- a/src/librustc/ty/adjustment.rs
+++ b/src/librustc/ty/adjustment.rs
@@ -234,8 +234,7 @@ impl<'a, 'gcx, 'tcx> ty::TyS<'tcx> {
         if let Some(method_ty) = method_type(method_call) {
             // Method calls always have all late-bound regions
             // fully instantiated.
-            let fn_ret = tcx.no_late_bound_regions(&method_ty.fn_ret()).unwrap();
-            adjusted_ty = fn_ret.unwrap();
+            adjusted_ty = tcx.no_late_bound_regions(&method_ty.fn_ret()).unwrap();
         }
         match adjusted_ty.builtin_deref(true, NoPreference) {
             Some(mt) => mt.ty,
diff --git a/src/librustc/ty/flags.rs b/src/librustc/ty/flags.rs
index 981b029da9b..fa38bacba2e 100644
--- a/src/librustc/ty/flags.rs
+++ b/src/librustc/ty/flags.rs
@@ -172,10 +172,7 @@ impl FlagComputation {
         let mut computation = FlagComputation::new();
 
         computation.add_tys(&fn_sig.0.inputs);
-
-        if let ty::FnConverging(output) = fn_sig.0.output {
-            computation.add_ty(output);
-        }
+        computation.add_ty(fn_sig.0.output);
 
         self.add_bound_computation(&computation);
     }
diff --git a/src/librustc/ty/fold.rs b/src/librustc/ty/fold.rs
index 3580013c2a9..3eeff6ee579 100644
--- a/src/librustc/ty/fold.rs
+++ b/src/librustc/ty/fold.rs
@@ -160,12 +160,6 @@ pub trait TypeFolder<'gcx: 'tcx, 'tcx> : Sized {
         sig.super_fold_with(self)
     }
 
-    fn fold_output(&mut self,
-                      output: &ty::FnOutput<'tcx>)
-                      -> ty::FnOutput<'tcx> {
-        output.super_fold_with(self)
-    }
-
     fn fold_bare_fn_ty(&mut self,
                        fty: &'tcx ty::BareFnTy<'tcx>)
                        -> &'tcx ty::BareFnTy<'tcx>
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index 29bbb8680e2..60d819bdad9 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -55,7 +55,7 @@ use hir::intravisit::Visitor;
 
 pub use self::sty::{Binder, DebruijnIndex};
 pub use self::sty::{BuiltinBound, BuiltinBounds, ExistentialBounds};
-pub use self::sty::{BareFnTy, FnSig, PolyFnSig, FnOutput, PolyFnOutput};
+pub use self::sty::{BareFnTy, FnSig, PolyFnSig};
 pub use self::sty::{ClosureTy, InferTy, ParamTy, ProjectionTy, TraitTy};
 pub use self::sty::{ClosureSubsts, TypeAndMut};
 pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
@@ -63,7 +63,6 @@ pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
 pub use self::sty::Issue32330;
 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
 pub use self::sty::BoundRegion::*;
-pub use self::sty::FnOutput::*;
 pub use self::sty::InferTy::*;
 pub use self::sty::Region::*;
 pub use self::sty::TypeVariants::*;
diff --git a/src/librustc/ty/relate.rs b/src/librustc/ty/relate.rs
index 8b9937d9828..1997eac9728 100644
--- a/src/librustc/ty/relate.rs
+++ b/src/librustc/ty/relate.rs
@@ -256,20 +256,11 @@ impl<'tcx> Relate<'tcx> for ty::FnSig<'tcx> {
         let inputs = relate_arg_vecs(relation,
                                      &a.inputs,
                                      &b.inputs)?;
+        let output = relation.relate(&a.output, &b.output)?;
 
-        let output = match (a.output, b.output) {
-            (ty::FnConverging(a_ty), ty::FnConverging(b_ty)) =>
-                Ok(ty::FnConverging(relation.relate(&a_ty, &b_ty)?)),
-            (ty::FnDiverging, ty::FnDiverging) =>
-                Ok(ty::FnDiverging),
-            (a, b) =>
-                Err(TypeError::ConvergenceMismatch(
-                    expected_found(relation, &(a != ty::FnDiverging), &(b != ty::FnDiverging)))),
-        }?;
-
-        return Ok(ty::FnSig {inputs: inputs,
-                             output: output,
-                             variadic: a.variadic});
+        Ok(ty::FnSig {inputs: inputs,
+                      output: output,
+                      variadic: a.variadic})
     }
 }
 
diff --git a/src/librustc/ty/structural_impls.rs b/src/librustc/ty/structural_impls.rs
index a7713bdfcb3..840703afd6f 100644
--- a/src/librustc/ty/structural_impls.rs
+++ b/src/librustc/ty/structural_impls.rs
@@ -220,18 +220,6 @@ impl<'a, 'tcx> Lift<'tcx> for ty::adjustment::AutoRef<'a> {
     }
 }
 
-impl<'a, 'tcx> Lift<'tcx> for ty::FnOutput<'a> {
-    type Lifted = ty::FnOutput<'tcx>;
-    fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
-        match *self {
-            ty::FnConverging(ty) => {
-                tcx.lift(&ty).map(ty::FnConverging)
-            }
-            ty::FnDiverging => Some(ty::FnDiverging)
-        }
-    }
-}
-
 impl<'a, 'tcx> Lift<'tcx> for ty::FnSig<'a> {
     type Lifted = ty::FnSig<'tcx>;
     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
@@ -587,26 +575,6 @@ impl<'tcx> TypeFoldable<'tcx> for ty::TypeAndMut<'tcx> {
     }
 }
 
-impl<'tcx> TypeFoldable<'tcx> for ty::FnOutput<'tcx> {
-    fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
-        match *self {
-            ty::FnConverging(ref ty) => ty::FnConverging(ty.fold_with(folder)),
-            ty::FnDiverging => ty::FnDiverging
-        }
-    }
-
-    fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
-        folder.fold_output(self)
-    }
-
-    fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
-        match *self {
-            ty::FnConverging(ref ty) => ty.visit_with(visitor),
-            ty::FnDiverging => false,
-        }
-    }
-}
-
 impl<'tcx> TypeFoldable<'tcx> for ty::FnSig<'tcx> {
     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
         ty::FnSig { inputs: self.inputs.fold_with(folder),
diff --git a/src/librustc/ty/sty.rs b/src/librustc/ty/sty.rs
index 6cc7eef1c6f..fec2c3b5ae5 100644
--- a/src/librustc/ty/sty.rs
+++ b/src/librustc/ty/sty.rs
@@ -29,7 +29,6 @@ use serialize::{Decodable, Decoder, Encodable, Encoder};
 
 use hir;
 
-use self::FnOutput::*;
 use self::InferTy::*;
 use self::TypeVariants::*;
 
@@ -477,50 +476,6 @@ pub struct ClosureTy<'tcx> {
     pub sig: PolyFnSig<'tcx>,
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
-pub enum FnOutput<'tcx> {
-    FnConverging(Ty<'tcx>),
-    FnDiverging
-}
-
-impl<'tcx> FnOutput<'tcx> {
-    pub fn diverges(&self, tcx: TyCtxt) -> bool {
-        match *self {
-            FnConverging(ref ty) => ty.is_empty(tcx),
-            FnDiverging => true,
-        }
-    }
-
-    pub fn unwrap(self) -> Ty<'tcx> {
-        match self {
-            ty::FnConverging(t) => t,
-            ty::FnDiverging => bug!()
-        }
-    }
-
-    pub fn unwrap_or(self, def: Ty<'tcx>) -> Ty<'tcx> {
-        match self {
-            ty::FnConverging(t) => t,
-            ty::FnDiverging => def
-        }
-    }
-
-    pub fn maybe_converging(self) -> Option<Ty<'tcx>> {
-        match self {
-            ty::FnConverging(t) => Some(t),
-            ty::FnDiverging => None
-        }
-    }
-}
-
-pub type PolyFnOutput<'tcx> = Binder<FnOutput<'tcx>>;
-
-impl<'tcx> PolyFnOutput<'tcx> {
-    pub fn diverges(&self, tcx: TyCtxt) -> bool {
-        self.0.diverges(tcx)
-    }
-}
-
 /// Signature of a function type, which I have arbitrarily
 /// decided to use to refer to the input/output types.
 ///
@@ -530,7 +485,7 @@ impl<'tcx> PolyFnOutput<'tcx> {
 #[derive(Clone, PartialEq, Eq, Hash)]
 pub struct FnSig<'tcx> {
     pub inputs: Vec<Ty<'tcx>>,
-    pub output: FnOutput<'tcx>,
+    pub output: Ty<'tcx>,
     pub variadic: bool
 }
 
@@ -543,7 +498,7 @@ impl<'tcx> PolyFnSig<'tcx> {
     pub fn input(&self, index: usize) -> ty::Binder<Ty<'tcx>> {
         self.map_bound_ref(|fn_sig| fn_sig.inputs[index])
     }
-    pub fn output(&self) -> ty::Binder<FnOutput<'tcx>> {
+    pub fn output(&self) -> ty::Binder<Ty<'tcx>> {
         self.map_bound_ref(|fn_sig| fn_sig.output.clone())
     }
     pub fn variadic(&self) -> bool {
@@ -1205,7 +1160,7 @@ impl<'a, 'gcx, 'tcx> TyS<'tcx> {
         self.fn_sig().inputs()
     }
 
-    pub fn fn_ret(&self) -> Binder<FnOutput<'tcx>> {
+    pub fn fn_ret(&self) -> Binder<Ty<'tcx>> {
         self.fn_sig().output()
     }
 
diff --git a/src/librustc/ty/walk.rs b/src/librustc/ty/walk.rs
index d46de6f7993..fef1e7a164c 100644
--- a/src/librustc/ty/walk.rs
+++ b/src/librustc/ty/walk.rs
@@ -110,10 +110,7 @@ fn push_subtypes<'tcx>(stack: &mut Vec<Ty<'tcx>>, parent_ty: Ty<'tcx>) {
 }
 
 fn push_sig_subtypes<'tcx>(stack: &mut Vec<Ty<'tcx>>, sig: &ty::PolyFnSig<'tcx>) {
-    match sig.0.output {
-        ty::FnConverging(output) => { stack.push(output); }
-        ty::FnDiverging => { }
-    }
+    stack.push(sig.0.output);
     push_reversed(stack, &sig.0.inputs);
 }
 
diff --git a/src/librustc/util/ppaux.rs b/src/librustc/util/ppaux.rs
index b7851f9879d..90ebf58f861 100644
--- a/src/librustc/util/ppaux.rs
+++ b/src/librustc/util/ppaux.rs
@@ -34,7 +34,7 @@ pub fn verbose() -> bool {
 fn fn_sig(f: &mut fmt::Formatter,
           inputs: &[Ty],
           variadic: bool,
-          output: ty::FnOutput)
+          output: Ty)
           -> fmt::Result {
     write!(f, "(")?;
     let mut inputs = inputs.iter();
@@ -48,18 +48,11 @@ fn fn_sig(f: &mut fmt::Formatter,
         }
     }
     write!(f, ")")?;
-
-    match output {
-        ty::FnConverging(ty) => {
-            if !ty.is_nil() {
-                write!(f, " -> {}", ty)?;
-            }
-            Ok(())
-        }
-        ty::FnDiverging => {
-            write!(f, " -> !")
-        }
+    if !output.is_nil() {
+        write!(f, " -> {}", output)?;
     }
+
+    Ok(())
 }
 
 /// Namespace of the path given to parameterized to print.
@@ -135,7 +128,7 @@ pub fn parameterized<GG>(f: &mut fmt::Formatter,
     if !verbose && fn_trait_kind.is_some() && projections.len() == 1 {
         let projection_ty = projections[0].ty;
         if let TyTuple(ref args) = substs.types.get_slice(subst::TypeSpace)[0].sty {
-            return fn_sig(f, args, false, ty::FnConverging(projection_ty));
+            return fn_sig(f, args, false, projection_ty);
         }
     }
 
diff --git a/src/librustc_borrowck/borrowck/mir/gather_moves.rs b/src/librustc_borrowck/borrowck/mir/gather_moves.rs
index e965dcc169c..b3feac2bdc5 100644
--- a/src/librustc_borrowck/borrowck/mir/gather_moves.rs
+++ b/src/librustc_borrowck/borrowck/mir/gather_moves.rs
@@ -9,7 +9,7 @@
 // except according to those terms.
 
 
-use rustc::ty::{FnOutput, TyCtxt};
+use rustc::ty::TyCtxt;
 use rustc::mir::repr::*;
 use rustc::util::nodemap::FnvHashMap;
 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
@@ -231,8 +231,7 @@ impl<'tcx> Index<MovePathIndex> for MovePathData<'tcx> {
     }
 }
 
-struct MovePathDataBuilder<'a, 'tcx: 'a> {
-    mir: &'a Mir<'tcx>,
+struct MovePathDataBuilder<'tcx> {
     pre_move_paths: Vec<PreMovePath<'tcx>>,
     rev_lookup: MovePathLookup<'tcx>,
 }
@@ -412,7 +411,7 @@ impl<'tcx> MovePathLookup<'tcx> {
     }
 }
 
-impl<'a, 'tcx> MovePathDataBuilder<'a, 'tcx> {
+impl<'tcx> MovePathDataBuilder<'tcx> {
     fn lookup(&mut self, lval: &Lvalue<'tcx>) -> Lookup<MovePathIndex> {
         let proj = match *lval {
             Lvalue::Var(var_idx) =>
@@ -528,7 +527,6 @@ fn gather_moves<'a, 'tcx>(mir: &Mir<'tcx>, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> MoveD
     // BlockContexts constructed on each iteration. (Moving is more
     // straight-forward than mutable borrows in this instance.)
     let mut builder = MovePathDataBuilder {
-        mir: mir,
         pre_move_paths: Vec::new(),
         rev_lookup: MovePathLookup::new(mir),
     };
@@ -632,13 +630,8 @@ fn gather_moves<'a, 'tcx>(mir: &Mir<'tcx>, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> MoveD
             TerminatorKind::Return => {
                 let source = Location { block: bb,
                                         index: bb_data.statements.len() };
-                if let FnOutput::FnConverging(_) = bb_ctxt.builder.mir.return_ty {
-                    debug!("gather_moves Return on_move_out_lval return {:?}", source);
-                    bb_ctxt.on_move_out_lval(SK::Return, &Lvalue::ReturnPointer, source);
-                } else {
-                    debug!("gather_moves Return on_move_out_lval \
-                            assuming unreachable return {:?}", source);
-                }
+                debug!("gather_moves Return on_move_out_lval return {:?}", source);
+                bb_ctxt.on_move_out_lval(SK::Return, &Lvalue::ReturnPointer, source);
             }
 
             TerminatorKind::If { ref cond, targets: _ } => {
@@ -749,15 +742,15 @@ fn gather_moves<'a, 'tcx>(mir: &Mir<'tcx>, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> MoveD
     }
 }
 
-struct BlockContext<'b, 'a: 'b, 'tcx: 'a> {
+struct BlockContext<'b, 'tcx: 'b> {
     _tcx: TyCtxt<'b, 'tcx, 'tcx>,
     moves: &'b mut Vec<MoveOut>,
-    builder: MovePathDataBuilder<'a, 'tcx>,
+    builder: MovePathDataBuilder<'tcx>,
     path_map: &'b mut Vec<Vec<MoveOutIndex>>,
     loc_map_bb: &'b mut Vec<Vec<MoveOutIndex>>,
 }
 
-impl<'b, 'a: 'b, 'tcx: 'a> BlockContext<'b, 'a, 'tcx> {
+impl<'b, 'tcx: 'b> BlockContext<'b, 'tcx> {
     fn on_move_out_lval(&mut self,
                         stmt_kind: StmtKind,
                         lval: &Lvalue<'tcx>,
diff --git a/src/librustc_driver/test.rs b/src/librustc_driver/test.rs
index 30fe38a0603..7711091685d 100644
--- a/src/librustc_driver/test.rs
+++ b/src/librustc_driver/test.rs
@@ -262,7 +262,7 @@ impl<'a, 'gcx, 'tcx> Env<'a, 'gcx, 'tcx> {
             abi: Abi::Rust,
             sig: ty::Binder(ty::FnSig {
                 inputs: input_args,
-                output: ty::FnConverging(output_ty),
+                output: output_ty,
                 variadic: false,
             }),
         }))
diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index d8ec79fb060..ed17f3533d4 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -1110,10 +1110,9 @@ impl LateLintPass for MutableTransmutes {
                 let typ = cx.tcx.node_id_to_type(expr.id);
                 match typ.sty {
                     ty::TyFnDef(_, _, ref bare_fn) if bare_fn.abi == RustIntrinsic => {
-                        if let ty::FnConverging(to) = bare_fn.sig.0.output {
-                            let from = bare_fn.sig.0.inputs[0];
-                            return Some((&from.sty, &to.sty));
-                        }
+                        let from = bare_fn.sig.0.inputs[0];
+                        let to = bare_fn.sig.0.output;
+                        return Some((&from.sty, &to.sty));
                     },
                     _ => ()
                 }
diff --git a/src/librustc_lint/types.rs b/src/librustc_lint/types.rs
index 27da78eceb4..0ac12d77b1d 100644
--- a/src/librustc_lint/types.rs
+++ b/src/librustc_lint/types.rs
@@ -573,16 +573,11 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
                 }
 
                 let sig = cx.erase_late_bound_regions(&bare_fn.sig);
-                match sig.output {
-                    ty::FnDiverging => {}
-                    ty::FnConverging(output) => {
-                        if !output.is_nil() {
-                            let r = self.check_type_for_ffi(cache, output);
-                            match r {
-                                FfiSafe => {}
-                                _ => { return r; }
-                            }
-                        }
+                if !sig.output.is_nil() {
+                    let r = self.check_type_for_ffi(cache, sig.output);
+                    match r {
+                        FfiSafe => {}
+                        _ => { return r; }
                     }
                 }
                 for arg in sig.inputs {
@@ -641,7 +636,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
         }
 
         if let hir::Return(ref ret_hir) = decl.output {
-            let ret_ty = sig.output.unwrap();
+            let ret_ty = sig.output;
             if !ret_ty.is_nil() {
                 self.check_type_for_ffi_and_report_errors(ret_hir.span, ret_ty);
             }
diff --git a/src/librustc_metadata/tydecode.rs b/src/librustc_metadata/tydecode.rs
index 96cf3b7e91c..29dd9ba8b1b 100644
--- a/src/librustc_metadata/tydecode.rs
+++ b/src/librustc_metadata/tydecode.rs
@@ -540,13 +540,7 @@ impl<'a,'tcx> TyDecoder<'a,'tcx> {
             'N' => false,
             r => bug!("bad variadic: {}", r),
         };
-        let output = match self.peek() {
-            'z' => {
-                self.pos += 1;
-                ty::FnDiverging
-            }
-            _ => ty::FnConverging(self.parse_ty())
-        };
+        let output = self.parse_ty();
         ty::Binder(ty::FnSig {inputs: inputs,
                               output: output,
                               variadic: variadic})
diff --git a/src/librustc_metadata/tyencode.rs b/src/librustc_metadata/tyencode.rs
index 26fcb9b1f9f..762a163da93 100644
--- a/src/librustc_metadata/tyencode.rs
+++ b/src/librustc_metadata/tyencode.rs
@@ -383,14 +383,7 @@ fn enc_fn_sig<'a, 'tcx>(w: &mut Cursor<Vec<u8>>, cx: &ctxt<'a, 'tcx>,
     } else {
         write!(w, "N");
     }
-    match fsig.0.output {
-        ty::FnConverging(result_type) => {
-            enc_ty(w, cx, result_type);
-        }
-        ty::FnDiverging => {
-            write!(w, "z");
-        }
-    }
+    enc_ty(w, cx, fsig.0.output);
 }
 
 pub fn enc_builtin_bounds(w: &mut Cursor<Vec<u8>>, _cx: &ctxt, bs: &ty::BuiltinBounds) {
diff --git a/src/librustc_mir/build/expr/into.rs b/src/librustc_mir/build/expr/into.rs
index 692f0d3e5ac..5c6286ae367 100644
--- a/src/librustc_mir/build/expr/into.rs
+++ b/src/librustc_mir/build/expr/into.rs
@@ -210,7 +210,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             ExprKind::Call { ty, fun, args } => {
                 let diverges = match ty.sty {
                     ty::TyFnDef(_, _, ref f) | ty::TyFnPtr(ref f) => {
-                        f.sig.0.output.diverges(this.hir.tcx())
+                        f.sig.0.output.is_empty(this.hir.tcx())
                     }
                     _ => false
                 };
diff --git a/src/librustc_mir/build/mod.rs b/src/librustc_mir/build/mod.rs
index 362e1e26fdf..e4e1c7999a6 100644
--- a/src/librustc_mir/build/mod.rs
+++ b/src/librustc_mir/build/mod.rs
@@ -162,7 +162,7 @@ macro_rules! unpack {
 pub fn construct_fn<'a, 'gcx, 'tcx, A>(hir: Cx<'a, 'gcx, 'tcx>,
                                        fn_id: ast::NodeId,
                                        arguments: A,
-                                       return_ty: ty::FnOutput<'gcx>,
+                                       return_ty: ty::Ty<'gcx>,
                                        ast_block: &'gcx hir::Block)
                                        -> (Mir<'tcx>, ScopeAuxiliaryVec)
     where A: Iterator<Item=(Ty<'gcx>, Option<&'gcx hir::Pat>)>
@@ -255,7 +255,7 @@ pub fn construct_const<'a, 'gcx, 'tcx>(hir: Cx<'a, 'gcx, 'tcx>,
     });
 
     let ty = tcx.expr_ty_adjusted(ast_expr);
-    builder.finish(vec![], IndexVec::new(), ty::FnConverging(ty))
+    builder.finish(vec![], IndexVec::new(), ty)
 }
 
 impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
@@ -287,7 +287,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
     fn finish(self,
               upvar_decls: Vec<UpvarDecl>,
               arg_decls: IndexVec<Arg, ArgDecl<'tcx>>,
-              return_ty: ty::FnOutput<'tcx>)
+              return_ty: ty::Ty<'tcx>)
               -> (Mir<'tcx>, ScopeAuxiliaryVec) {
         for (index, block) in self.cfg.basic_blocks.iter().enumerate() {
             if block.terminator.is_none() {
@@ -309,7 +309,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
 
     fn args_and_body<A>(&mut self,
                         mut block: BasicBlock,
-                        return_ty: ty::FnOutput<'tcx>,
+                        return_ty: ty::Ty<'tcx>,
                         arguments: A,
                         argument_extent: CodeExtent,
                         ast_block: &'gcx hir::Block)
@@ -350,11 +350,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
         }
 
         // FIXME(#32959): temporary hack for the issue at hand
-        let return_is_unit = if let ty::FnConverging(t) = return_ty {
-            t.is_nil()
-        } else {
-            false
-        };
+        let return_is_unit = return_ty.is_nil();
         // start the first basic block and translate the body
         unpack!(block = self.ast_block(&Lvalue::ReturnPointer, return_is_unit, block, ast_block));
 
diff --git a/src/librustc_mir/graphviz.rs b/src/librustc_mir/graphviz.rs
index d986d88dafc..72b6d7f0e5a 100644
--- a/src/librustc_mir/graphviz.rs
+++ b/src/librustc_mir/graphviz.rs
@@ -12,7 +12,7 @@ use dot;
 use rustc::hir::def_id::DefId;
 use rustc::mir::repr::*;
 use rustc::mir::mir_map::MirMap;
-use rustc::ty::{self, TyCtxt};
+use rustc::ty::TyCtxt;
 use std::fmt::Debug;
 use std::io::{self, Write};
 use syntax::ast::NodeId;
@@ -143,14 +143,7 @@ fn write_graph_label<'a, 'tcx, W: Write>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         write!(w, "{:?}: {}", Lvalue::Arg(Arg::new(i)), escape(&arg.ty))?;
     }
 
-    write!(w, ") -&gt; ")?;
-
-    // fn return type.
-    match mir.return_ty {
-        ty::FnOutput::FnConverging(ty) => write!(w, "{}", escape(ty))?,
-        ty::FnOutput::FnDiverging => write!(w, "!")?,
-    }
-
+    write!(w, ") -&gt; {}", escape(mir.return_ty))?;
     write!(w, r#"<br align="left"/>"#)?;
 
     // User variable types (including the user's name in a comment).
diff --git a/src/librustc_mir/hair/cx/expr.rs b/src/librustc_mir/hair/cx/expr.rs
index 28a23e2a499..bb6e9ba823c 100644
--- a/src/librustc_mir/hair/cx/expr.rs
+++ b/src/librustc_mir/hair/cx/expr.rs
@@ -97,9 +97,9 @@ impl<'tcx> Mirror<'tcx> for &'tcx hir::Expr {
 
                         let ref_ty = cx.tcx.no_late_bound_regions(&meth_ty.fn_ret());
                         let (region, mutbl) = match ref_ty {
-                            Some(ty::FnConverging(&ty::TyS {
+                            Some(&ty::TyS {
                                 sty: ty::TyRef(region, mt), ..
-                            })) => (region, mt.mutbl),
+                            }) => (region, mt.mutbl),
                             _ => span_bug!(expr.span, "autoderef returned bad type")
                         };
 
@@ -955,10 +955,8 @@ fn overloaded_lvalue<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
     let tables = cx.tcx.tables.borrow();
     let callee = &tables.method_map[&method_call];
     let ref_ty = callee.ty.fn_ret();
-    let ref_ty = cx.tcx.no_late_bound_regions(&ref_ty).unwrap().unwrap();
-    //                                              1~~~~~   2~~~~~
-    // (1) callees always have all late-bound regions fully instantiated,
-    // (2) overloaded methods don't return `!`
+    let ref_ty = cx.tcx.no_late_bound_regions(&ref_ty).unwrap();
+    // callees always have all late-bound regions fully instantiated,
 
     // construct the complete expression `foo()` for the overloaded call,
     // which will yield the &T type
diff --git a/src/librustc_mir/pretty.rs b/src/librustc_mir/pretty.rs
index 55e7408b0fd..c58491096b9 100644
--- a/src/librustc_mir/pretty.rs
+++ b/src/librustc_mir/pretty.rs
@@ -14,7 +14,7 @@ use rustc::hir::def_id::DefId;
 use rustc::mir::repr::*;
 use rustc::mir::mir_map::MirMap;
 use rustc::mir::transform::MirSource;
-use rustc::ty::{self, TyCtxt};
+use rustc::ty::TyCtxt;
 use rustc_data_structures::fnv::FnvHashMap;
 use rustc_data_structures::indexed_vec::{Idx};
 use std::fmt::Display;
@@ -320,16 +320,10 @@ fn write_mir_sig(tcx: TyCtxt, src: MirSource, mir: &Mir, w: &mut Write)
             write!(w, "{:?}: {}", Lvalue::Arg(i), arg.ty)?;
         }
 
-        write!(w, ") -> ")?;
-
-        // fn return type.
-        match mir.return_ty {
-            ty::FnOutput::FnConverging(ty) => write!(w, "{}", ty),
-            ty::FnOutput::FnDiverging => write!(w, "!"),
-        }
+        write!(w, ") -> {}", mir.return_ty)
     } else {
         assert!(mir.arg_decls.is_empty());
-        write!(w, ": {} =", mir.return_ty.unwrap())
+        write!(w, ": {} =", mir.return_ty)
     }
 }
 
diff --git a/src/librustc_mir/transform/promote_consts.rs b/src/librustc_mir/transform/promote_consts.rs
index eb0d8697f15..aaa20405b8d 100644
--- a/src/librustc_mir/transform/promote_consts.rs
+++ b/src/librustc_mir/transform/promote_consts.rs
@@ -25,7 +25,7 @@
 use rustc::mir::repr::*;
 use rustc::mir::visit::{LvalueContext, MutVisitor, Visitor};
 use rustc::mir::traversal::ReversePostorder;
-use rustc::ty::{self, TyCtxt};
+use rustc::ty::TyCtxt;
 use syntax_pos::Span;
 
 use build::Location;
@@ -299,7 +299,7 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
         let span = self.promoted.span;
         let new_operand = Operand::Constant(Constant {
             span: span,
-            ty: self.promoted.return_ty.unwrap(),
+            ty: self.promoted.return_ty,
             literal: Literal::Promoted {
                 index: Promoted::new(self.source.promoted.len())
             }
@@ -389,7 +389,7 @@ pub fn promote_candidates<'a, 'tcx>(mir: &mut Mir<'tcx>,
                     parent_scope: None
                 }).into_iter().collect(),
                 IndexVec::new(),
-                ty::FnConverging(ty),
+                ty,
                 IndexVec::new(),
                 IndexVec::new(),
                 IndexVec::new(),
diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
index 7ebc72bcc5f..57c0f66448d 100644
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@@ -416,7 +416,7 @@ impl<'a, 'tcx> Qualifier<'a, 'tcx, 'tcx> {
             }
         }
 
-        let return_ty = mir.return_ty.unwrap();
+        let return_ty = mir.return_ty;
         self.qualif = self.return_qualif.unwrap_or(Qualif::NOT_CONST);
 
         match self.mode {
@@ -991,7 +991,7 @@ impl<'tcx> MirMapPass<'tcx> for QualifyAndPromoteConstants {
 
             // Statics must be Sync.
             if mode == Mode::Static {
-                let ty = mir.return_ty.unwrap();
+                let ty = mir.return_ty;
                 tcx.infer_ctxt(None, None, Reveal::NotSpecializable).enter(|infcx| {
                     let cause = traits::ObligationCause::new(mir.span, id, traits::SharedStatic);
                     let mut fulfillment_cx = traits::FulfillmentContext::new();
diff --git a/src/librustc_mir/transform/type_check.rs b/src/librustc_mir/transform/type_check.rs
index 53329a85036..501b69bb12a 100644
--- a/src/librustc_mir/transform/type_check.rs
+++ b/src/librustc_mir/transform/type_check.rs
@@ -85,9 +85,7 @@ impl<'a, 'b, 'gcx, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'gcx, 'tcx> {
     }
 
     fn visit_mir(&mut self, mir: &Mir<'tcx>) {
-        if let ty::FnConverging(t) = mir.return_ty {
-            self.sanitize_type(&"return type", t);
-        }
+        self.sanitize_type(&"return type", mir.return_ty);
         for var_decl in &mir.var_decls {
             self.sanitize_type(var_decl, var_decl.ty);
         }
@@ -135,14 +133,7 @@ impl<'a, 'b, 'gcx, 'tcx> TypeVerifier<'a, 'b, 'gcx, 'tcx> {
             Lvalue::Static(def_id) =>
                 LvalueTy::Ty { ty: self.tcx().lookup_item_type(def_id).ty },
             Lvalue::ReturnPointer => {
-                if let ty::FnConverging(return_ty) = self.mir.return_ty {
-                    LvalueTy::Ty { ty: return_ty }
-                } else {
-                    LvalueTy::Ty {
-                        ty: span_mirbug_and_err!(
-                            self, lvalue, "return in diverging function")
-                    }
-                }
+                LvalueTy::Ty { ty: self.mir.return_ty }
             }
             Lvalue::Projection(ref proj) => {
                 let base_ty = self.sanitize_lvalue(&proj.base);
@@ -491,24 +482,20 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
                        sig: &ty::FnSig<'tcx>,
                        destination: &Option<(Lvalue<'tcx>, BasicBlock)>) {
         let tcx = self.tcx();
-        match (destination, sig.output) {
-            (&Some(..), ty::FnDiverging) => {
-                span_mirbug!(self, term, "call to diverging function {:?} with dest", sig);
-            }
-            (&Some((ref dest, _)), ty::FnConverging(ty)) => {
+        match *destination {
+            Some((ref dest, _)) => {
                 let dest_ty = dest.ty(mir, tcx).to_ty(tcx);
-                if let Err(terr) = self.sub_types(self.last_span, ty, dest_ty) {
+                if let Err(terr) = self.sub_types(self.last_span, sig.output, dest_ty) {
                     span_mirbug!(self, term,
                                  "call dest mismatch ({:?} <- {:?}): {:?}",
-                                 dest_ty, ty, terr);
+                                 dest_ty, sig.output, terr);
                 }
-            }
-            (&None, ty::FnDiverging) => {}
-            (&None, ty::FnConverging(ref ty)) => {
-                if !ty.is_empty(tcx) {
+            },
+            None => {
+                if !sig.output.is_empty(tcx) {
                     span_mirbug!(self, term, "call to converging function {:?} w/o dest", sig);
                 }
-            }
+            },
         }
     }
 
diff --git a/src/librustc_privacy/lib.rs b/src/librustc_privacy/lib.rs
index 7f5f09aa6b6..42239a7d5a4 100644
--- a/src/librustc_privacy/lib.rs
+++ b/src/librustc_privacy/lib.rs
@@ -440,7 +440,7 @@ impl<'a, 'tcx, 'v> Visitor<'v> for PrivacyVisitor<'a, 'tcx> {
                     let expr_ty = self.tcx.expr_ty(expr);
                     let def = match expr_ty.sty {
                         ty::TyFnDef(_, _, &ty::BareFnTy { sig: ty::Binder(ty::FnSig {
-                            output: ty::FnConverging(ty), ..
+                            output: ty, ..
                         }), ..}) => ty,
                         _ => expr_ty
                     }.ty_adt_def().unwrap();
diff --git a/src/librustc_save_analysis/lib.rs b/src/librustc_save_analysis/lib.rs
index 0580c51d9a1..16cd9186ce9 100644
--- a/src/librustc_save_analysis/lib.rs
+++ b/src/librustc_save_analysis/lib.rs
@@ -671,7 +671,6 @@ fn make_signature(decl: &ast::FnDecl, generics: &ast::Generics) -> String {
     sig.push_str(&decl.inputs.iter().map(arg_to_string).collect::<Vec<_>>().join(", "));
     sig.push(')');
     match decl.output {
-        ast::FunctionRetTy::None(_) => sig.push_str(" -> !"),
         ast::FunctionRetTy::Default(_) => {}
         ast::FunctionRetTy::Ty(ref t) => sig.push_str(&format!(" -> {}", ty_to_string(t))),
     }
diff --git a/src/librustc_trans/abi.rs b/src/librustc_trans/abi.rs
index 587c03af3ab..3a7fde6a36b 100644
--- a/src/librustc_trans/abi.rs
+++ b/src/librustc_trans/abi.rs
@@ -326,10 +326,7 @@ impl FnType {
             }
         };
 
-        let ret_ty = match sig.output {
-            ty::FnConverging(ret_ty) => ret_ty,
-            ty::FnDiverging => ccx.tcx().mk_nil()
-        };
+        let ret_ty = sig.output;
         let mut ret = arg_of(ret_ty, true);
 
         if !type_is_fat_ptr(ccx.tcx(), ret_ty) {
@@ -470,7 +467,7 @@ impl FnType {
             };
             // Fat pointers are returned by-value.
             if !self.ret.is_ignore() {
-                if !type_is_fat_ptr(ccx.tcx(), sig.output.unwrap()) {
+                if !type_is_fat_ptr(ccx.tcx(), sig.output) {
                     fixup(&mut self.ret);
                 }
             }
diff --git a/src/librustc_trans/base.rs b/src/librustc_trans/base.rs
index 1077cb296c1..70c3fdc269d 100644
--- a/src/librustc_trans/base.rs
+++ b/src/librustc_trans/base.rs
@@ -1972,7 +1972,7 @@ pub fn trans_named_tuple_constructor<'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
 
     let sig = ccx.tcx().erase_late_bound_regions(&ctor_ty.fn_sig());
     let sig = ccx.tcx().normalize_associated_type(&sig);
-    let result_ty = sig.output.unwrap();
+    let result_ty = sig.output;
 
     // Get location to store the result. If the user does not care about
     // the result, just make a stack slot
@@ -2054,7 +2054,7 @@ pub fn trans_ctor_shim<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
     if !fcx.fn_ty.ret.is_ignore() {
         let dest = fcx.get_ret_slot(bcx, "eret_slot");
         let dest_val = adt::MaybeSizedValue::sized(dest); // Can return unsized value
-        let repr = adt::represent_type(ccx, sig.output.unwrap());
+        let repr = adt::represent_type(ccx, sig.output);
         let mut llarg_idx = fcx.fn_ty.ret.is_indirect() as usize;
         let mut arg_idx = 0;
         for (i, arg_ty) in sig.inputs.into_iter().enumerate() {
diff --git a/src/librustc_trans/callee.rs b/src/librustc_trans/callee.rs
index 983ee564c35..56b378519b4 100644
--- a/src/librustc_trans/callee.rs
+++ b/src/librustc_trans/callee.rs
@@ -641,10 +641,7 @@ fn trans_call_inner<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
     let opt_llretslot = dest.and_then(|dest| match dest {
         expr::SaveIn(dst) => Some(dst),
         expr::Ignore => {
-            let needs_drop = || match output {
-                ty::FnConverging(ret_ty) => bcx.fcx.type_needs_drop(ret_ty),
-                ty::FnDiverging => false
-            };
+            let needs_drop = || bcx.fcx.type_needs_drop(output);
             if fn_ty.ret.is_indirect() || fn_ty.ret.cast.is_some() || needs_drop() {
                 // Push the out-pointer if we use an out-pointer for this
                 // return type, otherwise push "undef".
@@ -706,16 +703,16 @@ fn trans_call_inner<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
 
     // If the caller doesn't care about the result of this fn call,
     // drop the temporary slot we made.
-    match (dest, opt_llretslot, output) {
-        (Some(expr::Ignore), Some(llretslot), ty::FnConverging(ret_ty)) => {
+    match (dest, opt_llretslot) {
+        (Some(expr::Ignore), Some(llretslot)) => {
             // drop the value if it is not being saved.
-            bcx = glue::drop_ty(bcx, llretslot, ret_ty, debug_loc);
+            bcx = glue::drop_ty(bcx, llretslot, output, debug_loc);
             call_lifetime_end(bcx, llretslot);
         }
         _ => {}
     }
 
-    if output == ty::FnDiverging {
+    if output.is_empty(bcx.tcx()) {
         Unreachable(bcx);
     }
 
diff --git a/src/librustc_trans/closure.rs b/src/librustc_trans/closure.rs
index e53a5edfc66..77b2c43167c 100644
--- a/src/librustc_trans/closure.rs
+++ b/src/librustc_trans/closure.rs
@@ -201,7 +201,11 @@ pub fn trans_closure_body_via_mir<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
     trans_closure_expr(Dest::Ignore(ccx),
                        &hir::FnDecl {
                            inputs: P::new(),
-                           output: hir::NoReturn(DUMMY_SP),
+                           output: hir::Return(P(hir::Ty {
+                               id: DUMMY_NODE_ID,
+                               span: DUMMY_SP,
+                               node: hir::Ty_::TyNever,
+                           })),
                            variadic: false
                        },
                        &hir::Block {
diff --git a/src/librustc_trans/common.rs b/src/librustc_trans/common.rs
index dea5a1560e1..7683a572aaa 100644
--- a/src/librustc_trans/common.rs
+++ b/src/librustc_trans/common.rs
@@ -558,7 +558,7 @@ impl<'a, 'tcx> FunctionContext<'a, 'tcx> {
             abi: Abi::C,
             sig: ty::Binder(ty::FnSig {
                 inputs: vec![tcx.mk_mut_ptr(tcx.types.u8)],
-                output: ty::FnDiverging,
+                output: tcx.mk_empty(),
                 variadic: false
             }),
         }));
@@ -1240,8 +1240,8 @@ pub fn inlined_variant_def<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
            inlined_vid);
     let adt_def = match ctor_ty.sty {
         ty::TyFnDef(_, _, &ty::BareFnTy { sig: ty::Binder(ty::FnSig {
-            output: ty::FnConverging(ty), ..
-        }), ..}) => ty,
+            output, ..
+        }), ..}) => output,
         _ => ctor_ty
     }.ty_adt_def().unwrap();
     let variant_def_id = if ccx.tcx().map.is_inlined_node_id(inlined_vid) {
diff --git a/src/librustc_trans/debuginfo/metadata.rs b/src/librustc_trans/debuginfo/metadata.rs
index 4c58ce6b78c..08dfc97d67a 100644
--- a/src/librustc_trans/debuginfo/metadata.rs
+++ b/src/librustc_trans/debuginfo/metadata.rs
@@ -279,16 +279,9 @@ impl<'tcx> TypeMap<'tcx> {
                 }
 
                 unique_type_id.push_str(")->");
-                match sig.output {
-                    ty::FnConverging(ret_ty) => {
-                        let return_type_id = self.get_unique_type_id_of_type(cx, ret_ty);
-                        let return_type_id = self.get_unique_type_id_as_string(return_type_id);
-                        unique_type_id.push_str(&return_type_id[..]);
-                    }
-                    ty::FnDiverging => {
-                        unique_type_id.push_str("!");
-                    }
-                }
+                let return_type_id = self.get_unique_type_id_of_type(cx, sig.output);
+                let return_type_id = self.get_unique_type_id_as_string(return_type_id);
+                unique_type_id.push_str(&return_type_id[..]);
             },
             ty::TyClosure(_, substs) if substs.upvar_tys.is_empty() => {
                 push_debuginfo_type_name(cx, type_, false, &mut unique_type_id);
@@ -596,12 +589,9 @@ fn subroutine_type_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
     let mut signature_metadata: Vec<DIType> = Vec::with_capacity(signature.inputs.len() + 1);
 
     // return type
-    signature_metadata.push(match signature.output {
-        ty::FnConverging(ret_ty) => match ret_ty.sty {
-            ty::TyTuple(ref tys) if tys.is_empty() => ptr::null_mut(),
-            _ => type_metadata(cx, ret_ty, span)
-        },
-        ty::FnDiverging => diverging_type_metadata(cx)
+    signature_metadata.push(match signature.output.sty {
+        ty::TyTuple(ref tys) if tys.is_empty() => ptr::null_mut(),
+        _ => type_metadata(cx, signature.output, span)
     });
 
     // regular arguments
@@ -916,17 +906,6 @@ pub fn scope_metadata(fcx: &FunctionContext,
     }
 }
 
-pub fn diverging_type_metadata(cx: &CrateContext) -> DIType {
-    unsafe {
-        llvm::LLVMRustDIBuilderCreateBasicType(
-            DIB(cx),
-            "!\0".as_ptr() as *const _,
-            bytes_to_bits(0),
-            bytes_to_bits(0),
-            DW_ATE_unsigned)
-    }
-}
-
 fn basic_type_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
                                  t: Ty<'tcx>) -> DIType {
 
diff --git a/src/librustc_trans/debuginfo/mod.rs b/src/librustc_trans/debuginfo/mod.rs
index f2c7068565e..d6a4ce3c43a 100644
--- a/src/librustc_trans/debuginfo/mod.rs
+++ b/src/librustc_trans/debuginfo/mod.rs
@@ -17,8 +17,7 @@ use self::VariableKind::*;
 use self::utils::{DIB, span_start, create_DIArray, is_node_local_to_unit};
 use self::namespace::mangled_name_of_item;
 use self::type_names::compute_debuginfo_type_name;
-use self::metadata::{type_metadata, diverging_type_metadata};
-use self::metadata::{file_metadata, TypeMap};
+use self::metadata::{type_metadata, file_metadata, TypeMap};
 use self::source_loc::InternalDebugLocation::{self, UnknownLocation};
 
 use llvm;
@@ -325,12 +324,9 @@ pub fn create_function_debug_context<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
         let mut signature = Vec::with_capacity(sig.inputs.len() + 1);
 
         // Return type -- llvm::DIBuilder wants this at index 0
-        signature.push(match sig.output {
-            ty::FnConverging(ret_ty) => match ret_ty.sty {
-                ty::TyTuple(ref tys) if tys.is_empty() => ptr::null_mut(),
-                _ => type_metadata(cx, ret_ty, syntax_pos::DUMMY_SP)
-            },
-            ty::FnDiverging => diverging_type_metadata(cx)
+        signature.push(match sig.output.sty {
+            ty::TyTuple(ref tys) if tys.is_empty() => ptr::null_mut(),
+            _ => type_metadata(cx, sig.output, syntax_pos::DUMMY_SP)
         });
 
         let inputs = if abi == Abi::RustCall {
diff --git a/src/librustc_trans/debuginfo/type_names.rs b/src/librustc_trans/debuginfo/type_names.rs
index efd4acfeaa2..190b40d41c9 100644
--- a/src/librustc_trans/debuginfo/type_names.rs
+++ b/src/librustc_trans/debuginfo/type_names.rs
@@ -134,15 +134,9 @@ pub fn push_debuginfo_type_name<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 
             output.push(')');
 
-            match sig.output {
-                ty::FnConverging(result_type) if result_type.is_nil() => {}
-                ty::FnConverging(result_type) => {
-                    output.push_str(" -> ");
-                    push_debuginfo_type_name(cx, result_type, true, output);
-                }
-                ty::FnDiverging => {
-                    output.push_str(" -> !");
-                }
+            if !sig.output.is_nil() {
+                output.push_str(" -> ");
+                push_debuginfo_type_name(cx, sig.output, true, output);
             }
         },
         ty::TyClosure(..) => {
diff --git a/src/librustc_trans/declare.rs b/src/librustc_trans/declare.rs
index 324e8697eca..01eedb11ceb 100644
--- a/src/librustc_trans/declare.rs
+++ b/src/librustc_trans/declare.rs
@@ -111,7 +111,7 @@ pub fn declare_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, name: &str,
     let fty = FnType::new(ccx, abi, &sig, &[]);
     let llfn = declare_raw_fn(ccx, name, fty.cconv, fty.llvm_type(ccx));
 
-    if sig.output == ty::FnDiverging {
+    if sig.output.is_empty(ccx.tcx()) {
         llvm::Attribute::NoReturn.apply_llfn(Function, llfn);
     }
 
diff --git a/src/librustc_trans/expr.rs b/src/librustc_trans/expr.rs
index eed543aa31c..059532957b8 100644
--- a/src/librustc_trans/expr.rs
+++ b/src/librustc_trans/expr.rs
@@ -803,7 +803,7 @@ fn trans_index<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
             let ix_datum = unpack_datum!(bcx, trans(bcx, idx));
 
             let ref_ty = // invoked methods have LB regions instantiated:
-                bcx.tcx().no_late_bound_regions(&method_ty.fn_ret()).unwrap().unwrap();
+                bcx.tcx().no_late_bound_regions(&method_ty.fn_ret()).unwrap();
             let elt_ty = match ref_ty.builtin_deref(true, ty::NoPreference) {
                 None => {
                     span_bug!(index_expr.span,
@@ -2060,7 +2060,7 @@ fn deref_once<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
             };
 
             let ref_ty = // invoked methods have their LB regions instantiated
-                ccx.tcx().no_late_bound_regions(&method_ty.fn_ret()).unwrap().unwrap();
+                ccx.tcx().no_late_bound_regions(&method_ty.fn_ret()).unwrap();
             let scratch = rvalue_scratch_datum(bcx, ref_ty, "overloaded_deref");
 
             bcx = Callee::method(bcx, method)
diff --git a/src/librustc_trans/intrinsic.rs b/src/librustc_trans/intrinsic.rs
index 4980fad0cc3..066fe89aee5 100644
--- a/src/librustc_trans/intrinsic.rs
+++ b/src/librustc_trans/intrinsic.rs
@@ -132,7 +132,7 @@ pub fn trans_intrinsic_call<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
 
     // For `transmute` we can just trans the input expr directly into dest
     if name == "transmute" {
-        let llret_ty = type_of::type_of(ccx, ret_ty.unwrap());
+        let llret_ty = type_of::type_of(ccx, ret_ty);
         match args {
             callee::ArgExprs(arg_exprs) => {
                 assert_eq!(arg_exprs.len(), 1);
@@ -315,11 +315,6 @@ pub fn trans_intrinsic_call<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
         return Result::new(bcx, C_nil(ccx));
     }
 
-    let ret_ty = match ret_ty {
-        ty::FnConverging(ret_ty) => ret_ty,
-        ty::FnDiverging => bug!()
-    };
-
     let llret_ty = type_of::type_of(ccx, ret_ty);
 
     // Get location to store the result. If the user does
@@ -1226,7 +1221,7 @@ fn trans_gnu_try<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
 fn gen_fn<'a, 'tcx>(fcx: &FunctionContext<'a, 'tcx>,
                     name: &str,
                     inputs: Vec<Ty<'tcx>>,
-                    output: ty::FnOutput<'tcx>,
+                    output: ty::Ty<'tcx>,
                     trans: &mut for<'b> FnMut(Block<'b, 'tcx>))
                     -> ValueRef {
     let ccx = fcx.ccx;
@@ -1272,11 +1267,11 @@ fn get_rust_try_fn<'a, 'tcx>(fcx: &FunctionContext<'a, 'tcx>,
         abi: Abi::Rust,
         sig: ty::Binder(ty::FnSig {
             inputs: vec![i8p],
-            output: ty::FnOutput::FnConverging(tcx.mk_nil()),
+            output: tcx.mk_nil(),
             variadic: false,
         }),
     }));
-    let output = ty::FnOutput::FnConverging(tcx.types.i32);
+    let output = tcx.types.i32;
     let rust_try = gen_fn(fcx, "__rust_try", vec![fn_ty, i8p, i8p], output, trans);
     ccx.rust_try_fn().set(Some(rust_try));
     return rust_try
diff --git a/src/librustc_trans/mir/analyze.rs b/src/librustc_trans/mir/analyze.rs
index d6dbefec034..784e4a32f94 100644
--- a/src/librustc_trans/mir/analyze.rs
+++ b/src/librustc_trans/mir/analyze.rs
@@ -19,6 +19,7 @@ use rustc::mir::visit::{Visitor, LvalueContext};
 use rustc::mir::traversal;
 use common::{self, Block, BlockAndBuilder};
 use glue;
+use std::iter;
 use super::rvalue;
 
 pub fn lvalue_locals<'bcx, 'tcx>(bcx: Block<'bcx,'tcx>,
@@ -31,7 +32,7 @@ pub fn lvalue_locals<'bcx, 'tcx>(bcx: Block<'bcx,'tcx>,
     let local_types = mir.arg_decls.iter().map(|a| a.ty)
                .chain(mir.var_decls.iter().map(|v| v.ty))
                .chain(mir.temp_decls.iter().map(|t| t.ty))
-               .chain(mir.return_ty.maybe_converging());
+               .chain(iter::once(mir.return_ty));
     for (index, ty) in local_types.enumerate() {
         let ty = bcx.monomorphize(&ty);
         debug!("local {} has type {:?}", index, ty);
diff --git a/src/librustc_trans/mir/block.rs b/src/librustc_trans/mir/block.rs
index b1fd3e88d75..56d02fa1fac 100644
--- a/src/librustc_trans/mir/block.rs
+++ b/src/librustc_trans/mir/block.rs
@@ -525,7 +525,7 @@ impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
                             // Make a fake operand for store_return
                             let op = OperandRef {
                                 val: Ref(dst),
-                                ty: sig.output.unwrap()
+                                ty: sig.output,
                             };
                             self.store_return(&bcx, ret_dest, fn_ty.ret, op);
                         }
@@ -563,7 +563,7 @@ impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
                             debug_loc.apply_to_bcx(ret_bcx);
                             let op = OperandRef {
                                 val: Immediate(invokeret),
-                                ty: sig.output.unwrap()
+                                ty: sig.output,
                             };
                             self.store_return(&ret_bcx, ret_dest, fn_ty.ret, op);
                         });
@@ -574,7 +574,7 @@ impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
                     if let Some((_, target)) = *destination {
                         let op = OperandRef {
                             val: Immediate(llret),
-                            ty: sig.output.unwrap()
+                            ty: sig.output,
                         };
                         self.store_return(&bcx, ret_dest, fn_ty.ret, op);
                         funclet_br(self, bcx, target);
diff --git a/src/librustc_trans/mir/mod.rs b/src/librustc_trans/mir/mod.rs
index 8f723d288c9..727b680541d 100644
--- a/src/librustc_trans/mir/mod.rs
+++ b/src/librustc_trans/mir/mod.rs
@@ -26,6 +26,7 @@ use syntax::parse::token::keywords;
 
 use std::ops::Deref;
 use std::rc::Rc;
+use std::iter;
 
 use basic_block::BasicBlock;
 
@@ -183,7 +184,7 @@ pub fn trans_mir<'blk, 'tcx: 'blk>(fcx: &'blk FunctionContext<'blk, 'tcx>) {
 
         let locals = mir.temp_decls.iter().enumerate().map(|(i, decl)| {
             (mir::Lvalue::Temp(mir::Temp::new(i)), decl.ty)
-        }).chain(mir.return_ty.maybe_converging().map(|ty| (mir::Lvalue::ReturnPointer, ty)));
+        }).chain(iter::once((mir::Lvalue::ReturnPointer, mir.return_ty)));
 
         args.into_iter().chain(vars).chain(locals.map(|(lvalue, ty)| {
             let ty = bcx.monomorphize(&ty);
diff --git a/src/librustc_trans/trans_item.rs b/src/librustc_trans/trans_item.rs
index ef756a7addd..9f4f8fc990a 100644
--- a/src/librustc_trans/trans_item.rs
+++ b/src/librustc_trans/trans_item.rs
@@ -233,7 +233,7 @@ impl<'a, 'tcx> TransItem<'tcx> {
 
         let sig = ty::FnSig {
             inputs: vec![tcx.mk_mut_ptr(tcx.types.i8)],
-            output: ty::FnOutput::FnConverging(tcx.mk_nil()),
+            output: tcx.mk_nil(),
             variadic: false,
         };
 
@@ -516,15 +516,9 @@ pub fn push_unique_type_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
             output.push(')');
 
-            match sig.output {
-                ty::FnConverging(result_type) if result_type.is_nil() => {}
-                ty::FnConverging(result_type) => {
-                    output.push_str(" -> ");
-                    push_unique_type_name(tcx, result_type, output);
-                }
-                ty::FnDiverging => {
-                    output.push_str(" -> !");
-                }
+            if !sig.output.is_nil() {
+                output.push_str(" -> ");
+                push_unique_type_name(tcx, sig.output, output);
             }
         },
         ty::TyClosure(def_id, ref closure_substs) => {
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index 1af171eb468..74fe3172b2a 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -1923,11 +1923,10 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
 
         let output_ty = match decl.output {
             hir::Return(ref output) =>
-                ty::FnConverging(self.convert_ty_with_lifetime_elision(implied_output_region,
-                                                                       &output,
-                                                                       ret_anon_scope)),
-            hir::DefaultReturn(..) => ty::FnConverging(self.tcx().mk_nil()),
-            hir::NoReturn(..) => ty::FnDiverging
+                self.convert_ty_with_lifetime_elision(implied_output_region,
+                                                      &output,
+                                                      ret_anon_scope),
+            hir::DefaultReturn(..) => self.tcx().mk_nil(),
         };
 
         (self.tcx().mk_bare_fn(ty::BareFnTy {
@@ -2070,11 +2069,10 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
             _ if is_infer && expected_ret_ty.is_some() =>
                 expected_ret_ty.unwrap(),
             _ if is_infer =>
-                ty::FnConverging(self.ty_infer(None, None, None, decl.output.span())),
+                self.ty_infer(None, None, None, decl.output.span()),
             hir::Return(ref output) =>
-                ty::FnConverging(self.ast_ty_to_ty(&rb, &output)),
+                self.ast_ty_to_ty(&rb, &output),
             hir::DefaultReturn(..) => bug!(),
-            hir::NoReturn(..) => ty::FnDiverging
         };
 
         debug!("ty_of_closure: input_tys={:?}", input_tys);
diff --git a/src/librustc_typeck/check/callee.rs b/src/librustc_typeck/check/callee.rs
index e73c3aa352b..985c3be1496 100644
--- a/src/librustc_typeck/check/callee.rs
+++ b/src/librustc_typeck/check/callee.rs
@@ -213,7 +213,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 // set up all the node type bindings.
                 error_fn_sig = ty::Binder(ty::FnSig {
                     inputs: self.err_args(arg_exprs.len()),
-                    output: ty::FnConverging(self.tcx.types.err),
+                    output: self.tcx.types.err,
                     variadic: false
                 });
 
@@ -345,10 +345,9 @@ impl<'gcx, 'tcx> DeferredCallResolution<'gcx, 'tcx> for CallResolution<'gcx, 'tc
                     fcx.demand_eqtype(self.call_expr.span, self_arg_ty, method_arg_ty);
                 }
 
-                let nilty = fcx.tcx.mk_nil();
                 fcx.demand_eqtype(self.call_expr.span,
-                                  method_sig.output.unwrap_or(nilty),
-                                  self.fn_sig.output.unwrap_or(nilty));
+                                  method_sig.output,
+                                  self.fn_sig.output);
 
                 fcx.write_overloaded_call_method_map(self.call_expr, method_callee);
             }
diff --git a/src/librustc_typeck/check/closure.rs b/src/librustc_typeck/check/closure.rs
index d3396eb4c1b..3acb8017eec 100644
--- a/src/librustc_typeck/check/closure.rs
+++ b/src/librustc_typeck/check/closure.rs
@@ -221,7 +221,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
         let fn_sig = ty::FnSig {
             inputs: input_tys,
-            output: ty::FnConverging(ret_param_ty),
+            output: ret_param_ty,
             variadic: false
         };
         debug!("deduce_sig_from_projection: fn_sig {:?}", fn_sig);
diff --git a/src/librustc_typeck/check/intrinsic.rs b/src/librustc_typeck/check/intrinsic.rs
index 4788911662d..38772470f3f 100644
--- a/src/librustc_typeck/check/intrinsic.rs
+++ b/src/librustc_typeck/check/intrinsic.rs
@@ -31,7 +31,7 @@ fn equate_intrinsic_type<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
                                    n_tps: usize,
                                    abi: Abi,
                                    inputs: Vec<ty::Ty<'tcx>>,
-                                   output: ty::FnOutput<'tcx>) {
+                                   output: ty::Ty<'tcx>) {
     let tcx = ccx.tcx;
     let def_id = tcx.map.local_def_id(it.id);
     let i_ty = tcx.lookup_item_type(def_id);
@@ -104,9 +104,9 @@ pub fn check_intrinsic_type(ccx: &CrateCtxt, it: &hir::ForeignItem) {
                 return;
             }
         };
-        (n_tps, inputs, ty::FnConverging(output))
+        (n_tps, inputs, output)
     } else if &name[..] == "abort" || &name[..] == "unreachable" {
-        (0, Vec::new(), ty::FnConverging(tcx.mk_empty()))
+        (0, Vec::new(), tcx.mk_empty())
     } else {
         let (n_tps, inputs, output) = match &name[..] {
             "breakpoint" => (0, Vec::new(), tcx.mk_nil()),
@@ -291,7 +291,7 @@ pub fn check_intrinsic_type(ccx: &CrateCtxt, it: &hir::ForeignItem) {
                     abi: Abi::Rust,
                     sig: ty::Binder(FnSig {
                         inputs: vec![mut_u8],
-                        output: ty::FnOutput::FnConverging(tcx.mk_nil()),
+                        output: tcx.mk_nil(),
                         variadic: false,
                     }),
                 });
@@ -304,7 +304,7 @@ pub fn check_intrinsic_type(ccx: &CrateCtxt, it: &hir::ForeignItem) {
                 return;
             }
         };
-        (n_tps, inputs, ty::FnConverging(output))
+        (n_tps, inputs, output)
     };
     equate_intrinsic_type(ccx, it, n_tps, Abi::RustIntrinsic, inputs, output)
 }
@@ -377,7 +377,7 @@ pub fn check_platform_intrinsic_type(ccx: &CrateCtxt,
                     }
                     match_intrinsic_type_to_type(ccx, "return value", it.span,
                                                  &mut structural_to_nomimal,
-                                                 &intr.output, sig.output.unwrap());
+                                                 &intr.output, sig.output);
                     return
                 }
                 None => {
@@ -390,7 +390,7 @@ pub fn check_platform_intrinsic_type(ccx: &CrateCtxt,
     };
 
     equate_intrinsic_type(ccx, it, n_tps, Abi::PlatformIntrinsic,
-                          inputs, ty::FnConverging(output))
+                          inputs, output)
 }
 
 // walk the expected type and the actual type in lock step, checking they're
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 89a4bc4cac6..6d19babf41f 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -372,7 +372,7 @@ pub struct FnCtxt<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
     // expects the types within the function to be consistent.
     err_count_on_creation: usize,
 
-    ret_ty: ty::FnOutput<'tcx>,
+    ret_ty: ty::Ty<'tcx>,
 
     ps: RefCell<UnsafetyState>,
 
@@ -676,14 +676,9 @@ fn check_fn<'a, 'gcx, 'tcx>(inherited: &'a Inherited<'a, 'gcx, 'tcx>,
     let mut fcx = FnCtxt::new(inherited, fn_sig.output, body.id);
     *fcx.ps.borrow_mut() = UnsafetyState::function(unsafety, unsafety_id);
 
-    fn_sig.output = match fcx.ret_ty {
-        ty::FnConverging(orig_ret_ty) => {
-            fcx.require_type_is_sized(orig_ret_ty, decl.output.span(), traits::ReturnType);
-            ty::FnConverging(fcx.instantiate_anon_types(&orig_ret_ty))
-        }
-        ty::FnDiverging => ty::FnDiverging
-    };
-    fcx.ret_ty = fn_sig.output;
+    fcx.require_type_is_sized(fcx.ret_ty, decl.output.span(), traits::ReturnType);
+    fcx.ret_ty = fcx.instantiate_anon_types(&fcx.ret_ty);
+    fn_sig.output = fcx.ret_ty;
 
     {
         let mut visit = GatherLocalsVisitor { fcx: &fcx, };
@@ -714,10 +709,7 @@ fn check_fn<'a, 'gcx, 'tcx>(inherited: &'a Inherited<'a, 'gcx, 'tcx>,
 
     inherited.tables.borrow_mut().liberated_fn_sigs.insert(fn_id, fn_sig);
 
-    fcx.check_block_with_expected(body, match fcx.ret_ty {
-        ty::FnConverging(result_type) => ExpectHasType(result_type),
-        ty::FnDiverging => NoExpectation
-    });
+    fcx.check_block_with_expected(body, ExpectHasType(fcx.ret_ty));
 
     fcx
 }
@@ -1168,7 +1160,7 @@ fn check_const_with_type<'a, 'tcx>(ccx: &'a CrateCtxt<'a, 'tcx>,
                                    expected_type: Ty<'tcx>,
                                    id: ast::NodeId) {
     ccx.inherited(id).enter(|inh| {
-        let fcx = FnCtxt::new(&inh, ty::FnConverging(expected_type), expr.id);
+        let fcx = FnCtxt::new(&inh, expected_type, expr.id);
         fcx.require_type_is_sized(expected_type, expr.span, traits::ConstSized);
 
         // Gather locals in statics (because of block expressions).
@@ -1465,7 +1457,7 @@ enum TupleArgumentsFlag {
 
 impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
     pub fn new(inh: &'a Inherited<'a, 'gcx, 'tcx>,
-               rty: ty::FnOutput<'tcx>,
+               rty: ty::Ty<'tcx>,
                body_id: ast::NodeId)
                -> FnCtxt<'a, 'gcx, 'tcx> {
         FnCtxt {
@@ -2288,7 +2280,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         // extract method return type, which will be &T;
         // all LB regions should have been instantiated during method lookup
         let ret_ty = method.ty.fn_ret();
-        let ret_ty = self.tcx.no_late_bound_regions(&ret_ty).unwrap().unwrap();
+        let ret_ty = self.tcx.no_late_bound_regions(&ret_ty).unwrap();
 
         // method returns &T, but the type as visible to user is T, so deref
         ret_ty.builtin_deref(true, NoPreference).unwrap()
@@ -2417,7 +2409,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                    args_no_rcvr: &'gcx [P<hir::Expr>],
                                    tuple_arguments: TupleArgumentsFlag,
                                    expected: Expectation<'tcx>)
-                                   -> ty::FnOutput<'tcx> {
+                                   -> ty::Ty<'tcx> {
         if method_fn_ty.references_error() {
             let err_inputs = self.err_args(args_no_rcvr.len());
 
@@ -2428,7 +2420,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
             self.check_argument_types(sp, &err_inputs[..], &[], args_no_rcvr,
                                       false, tuple_arguments);
-            ty::FnConverging(self.tcx.types.err)
+            self.tcx.types.err
         } else {
             match method_fn_ty.sty {
                 ty::TyFnDef(_, _, ref fty) => {
@@ -2688,11 +2680,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
     fn write_call(&self,
                   call_expr: &hir::Expr,
-                  output: ty::FnOutput<'tcx>) {
-        self.write_ty_expr(call_expr.id, match output {
-            ty::FnConverging(output_ty) => output_ty,
-            ty::FnDiverging => self.next_diverging_ty_var()
-        });
+                  output: ty::Ty<'tcx>) {
+        self.write_ty_expr(call_expr.id, output);
     }
 
     // AST fragment checking
@@ -2815,35 +2804,31 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
     fn expected_types_for_fn_args(&self,
                                   call_span: Span,
                                   expected_ret: Expectation<'tcx>,
-                                  formal_ret: ty::FnOutput<'tcx>,
+                                  formal_ret: ty::Ty<'tcx>,
                                   formal_args: &[Ty<'tcx>])
                                   -> Vec<Ty<'tcx>> {
         let expected_args = expected_ret.only_has_type(self).and_then(|ret_ty| {
-            if let ty::FnConverging(formal_ret_ty) = formal_ret {
-                self.commit_regions_if_ok(|| {
-                    // Attempt to apply a subtyping relationship between the formal
-                    // return type (likely containing type variables if the function
-                    // is polymorphic) and the expected return type.
-                    // No argument expectations are produced if unification fails.
-                    let origin = TypeOrigin::Misc(call_span);
-                    let ures = self.sub_types(false, origin, formal_ret_ty, ret_ty);
-                    // FIXME(#15760) can't use try! here, FromError doesn't default
-                    // to identity so the resulting type is not constrained.
-                    match ures {
-                        // FIXME(#32730) propagate obligations
-                        Ok(InferOk { obligations, .. }) => assert!(obligations.is_empty()),
-                        Err(e) => return Err(e),
-                    }
+            self.commit_regions_if_ok(|| {
+                // Attempt to apply a subtyping relationship between the formal
+                // return type (likely containing type variables if the function
+                // is polymorphic) and the expected return type.
+                // No argument expectations are produced if unification fails.
+                let origin = TypeOrigin::Misc(call_span);
+                let ures = self.sub_types(false, origin, formal_ret, ret_ty);
+                // FIXME(#15760) can't use try! here, FromError doesn't default
+                // to identity so the resulting type is not constrained.
+                match ures {
+                    // FIXME(#32730) propagate obligations
+                    Ok(InferOk { obligations, .. }) => assert!(obligations.is_empty()),
+                    Err(e) => return Err(e),
+                }
 
-                    // Record all the argument types, with the substitutions
-                    // produced from the above subtyping unification.
-                    Ok(formal_args.iter().map(|ty| {
-                        self.resolve_type_vars_if_possible(ty)
-                    }).collect())
-                }).ok()
-            } else {
-                None
-            }
+                // Record all the argument types, with the substitutions
+                // produced from the above subtyping unification.
+                Ok(formal_args.iter().map(|ty| {
+                    self.resolve_type_vars_if_possible(ty)
+                }).collect())
+            }).ok()
         }).unwrap_or(vec![]);
         debug!("expected_types_for_fn_args(formal={:?} -> {:?}, expected={:?} -> {:?})",
                formal_args, formal_ret,
@@ -3503,32 +3488,19 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
           hir::ExprBreak(_) => { self.write_empty(id); }
           hir::ExprAgain(_) => { self.write_empty(id); }
           hir::ExprRet(ref expr_opt) => {
-            match self.ret_ty {
-                ty::FnConverging(result_type) => {
-                    if let Some(ref e) = *expr_opt {
-                        self.check_expr_coercable_to_type(&e, result_type);
-                    } else {
-                        let eq_result = self.eq_types(false,
-                                                      TypeOrigin::Misc(expr.span),
-                                                      result_type,
-                                                      tcx.mk_nil())
-                            // FIXME(#32730) propagate obligations
-                            .map(|InferOk { obligations, .. }| assert!(obligations.is_empty()));
-                        if eq_result.is_err() {
-                            struct_span_err!(tcx.sess, expr.span, E0069,
-                                     "`return;` in a function whose return type is not `()`")
-                                .span_label(expr.span, &format!("return type is not ()"))
-                                .emit();
-                        }
-                    }
-                }
-                ty::FnDiverging => {
-                    if let Some(ref e) = *expr_opt {
-                        self.check_expr(&e);
-                    }
-                    struct_span_err!(tcx.sess, expr.span, E0166,
-                        "`return` in a function declared as diverging")
-                        .span_label(expr.span, &format!("diverging function cannot return"))
+            if let Some(ref e) = *expr_opt {
+                self.check_expr_coercable_to_type(&e, self.ret_ty);
+            } else {
+                let eq_result = self.eq_types(false,
+                                              TypeOrigin::Misc(expr.span),
+                                              self.ret_ty,
+                                              tcx.mk_nil())
+                    // FIXME(#32730) propagate obligations
+                    .map(|InferOk { obligations, .. }| assert!(obligations.is_empty()));
+                if eq_result.is_err() {
+                    struct_span_err!(tcx.sess, expr.span, E0069,
+                             "`return;` in a function whose return type is not `()`")
+                        .span_label(expr.span, &format!("return type is not ()"))
                         .emit();
                 }
             }
diff --git a/src/librustc_typeck/check/op.rs b/src/librustc_typeck/check/op.rs
index 17da3cd3490..b8db8e226ab 100644
--- a/src/librustc_typeck/check/op.rs
+++ b/src/librustc_typeck/check/op.rs
@@ -343,7 +343,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 // extract return type for method; all late bound regions
                 // should have been instantiated by now
                 let ret_ty = method_ty.fn_ret();
-                Ok(self.tcx.no_late_bound_regions(&ret_ty).unwrap().unwrap())
+                Ok(self.tcx.no_late_bound_regions(&ret_ty).unwrap())
             }
             None => {
                 Err(())
diff --git a/src/librustc_typeck/check/regionck.rs b/src/librustc_typeck/check/regionck.rs
index f3a6442f35d..22ffcfbaae1 100644
--- a/src/librustc_typeck/check/regionck.rs
+++ b/src/librustc_typeck/check/regionck.rs
@@ -311,7 +311,7 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
         let fn_sig_tys: Vec<_> =
             fn_sig.inputs.iter()
                          .cloned()
-                         .chain(Some(fn_sig.output.unwrap_or(self.tcx.types.bool)))
+                         .chain(Some(fn_sig.output))
                          .collect();
 
         let old_body_id = self.set_body_id(body.id);
@@ -708,7 +708,7 @@ impl<'a, 'gcx, 'tcx, 'v> Visitor<'v> for RegionCtxt<'a, 'gcx, 'tcx> {
                                             None::<hir::Expr>.iter(), true);
                         // late-bound regions in overloaded method calls are instantiated
                         let fn_ret = self.tcx.no_late_bound_regions(&method.ty.fn_ret());
-                        fn_ret.unwrap().unwrap()
+                        fn_ret.unwrap()
                     }
                     None => self.resolve_node_type(base.id)
                 };
@@ -980,14 +980,9 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
                     // Specialized version of constrain_call.
                     self.type_must_outlive(infer::CallRcvr(deref_expr.span),
                                            self_ty, r_deref_expr);
-                    match fn_sig.output {
-                        ty::FnConverging(return_type) => {
-                            self.type_must_outlive(infer::CallReturn(deref_expr.span),
-                                                   return_type, r_deref_expr);
-                            return_type
-                        }
-                        ty::FnDiverging => bug!()
-                    }
+                    self.type_must_outlive(infer::CallReturn(deref_expr.span),
+                                           fn_sig.output, r_deref_expr);
+                    fn_sig.output
                 }
                 None => derefd_ty
             };
diff --git a/src/librustc_typeck/check/wfcheck.rs b/src/librustc_typeck/check/wfcheck.rs
index e2080906ca2..2e629dc4312 100644
--- a/src/librustc_typeck/check/wfcheck.rs
+++ b/src/librustc_typeck/check/wfcheck.rs
@@ -51,7 +51,7 @@ impl<'a, 'gcx, 'tcx> CheckWfFcxBuilder<'a, 'gcx, 'tcx> {
         let id = self.id;
         let span = self.span;
         self.inherited.enter(|inh| {
-            let fcx = FnCtxt::new(&inh, ty::FnDiverging, id);
+            let fcx = FnCtxt::new(&inh, inh.ccx.tcx.mk_empty(), id);
             let wf_tys = f(&fcx, &mut CheckTypeWellFormedVisitor {
                 ccx: fcx.ccx,
                 code: code
@@ -394,15 +394,10 @@ impl<'ccx, 'gcx> CheckTypeWellFormedVisitor<'ccx, 'gcx> {
         }
         implied_bounds.extend(sig.inputs);
 
-        match sig.output {
-            ty::FnConverging(output) => {
-                fcx.register_wf_obligation(output, span, self.code.clone());
+        fcx.register_wf_obligation(sig.output, span, self.code.clone());
 
-                // FIXME(#25759) return types should not be implied bounds
-                implied_bounds.push(output);
-            }
-            ty::FnDiverging => { }
-        }
+        // FIXME(#25759) return types should not be implied bounds
+        implied_bounds.push(sig.output);
 
         self.check_where_clauses(fcx, span, predicates);
     }
diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index 75bfad053a3..d38065f4f12 100644
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -971,7 +971,7 @@ fn convert_variant_ctor<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
                 abi: abi::Abi::Rust,
                 sig: ty::Binder(ty::FnSig {
                     inputs: inputs,
-                    output: ty::FnConverging(scheme.ty),
+                    output: scheme.ty,
                     variadic: false
                 })
             }))
@@ -2155,11 +2155,9 @@ fn compute_type_scheme_of_foreign_fn_decl<'a, 'tcx>(
 
     let output = match decl.output {
         hir::Return(ref ty) =>
-            ty::FnConverging(AstConv::ast_ty_to_ty(&ccx.icx(ast_generics), &rb, &ty)),
+            AstConv::ast_ty_to_ty(&ccx.icx(ast_generics), &rb, &ty),
         hir::DefaultReturn(..) =>
-            ty::FnConverging(ccx.tcx.mk_nil()),
-        hir::NoReturn(..) =>
-            ty::FnDiverging
+            ccx.tcx.mk_nil(),
     };
 
     // feature gate SIMD types in FFI, since I (huonw) am not sure the
@@ -2180,7 +2178,7 @@ fn compute_type_scheme_of_foreign_fn_decl<'a, 'tcx>(
             check(&input.ty, ty)
         }
         if let hir::Return(ref ty) = decl.output {
-            check(&ty, output.unwrap())
+            check(&ty, output)
         }
     }
 
diff --git a/src/librustc_typeck/lib.rs b/src/librustc_typeck/lib.rs
index 0dd4bc41439..11743ade2d4 100644
--- a/src/librustc_typeck/lib.rs
+++ b/src/librustc_typeck/lib.rs
@@ -238,7 +238,7 @@ fn check_main_fn_ty(ccx: &CrateCtxt,
                 abi: Abi::Rust,
                 sig: ty::Binder(ty::FnSig {
                     inputs: Vec::new(),
-                    output: ty::FnConverging(tcx.mk_nil()),
+                    output: tcx.mk_nil(),
                     variadic: false
                 })
             }));
@@ -294,7 +294,7 @@ fn check_start_fn_ty(ccx: &CrateCtxt,
                         tcx.types.isize,
                         tcx.mk_imm_ptr(tcx.mk_imm_ptr(tcx.types.u8))
                     ),
-                    output: ty::FnConverging(tcx.types.isize),
+                    output: tcx.types.isize,
                     variadic: false,
                 }),
             }));
diff --git a/src/librustc_typeck/variance/constraints.rs b/src/librustc_typeck/variance/constraints.rs
index 918e0386a68..3d4e71bed46 100644
--- a/src/librustc_typeck/variance/constraints.rs
+++ b/src/librustc_typeck/variance/constraints.rs
@@ -490,9 +490,7 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
         for &input in &sig.0.inputs {
             self.add_constraints_from_ty(generics, input, contra);
         }
-        if let ty::FnConverging(result_type) = sig.0.output {
-            self.add_constraints_from_ty(generics, result_type, variance);
-        }
+        self.add_constraints_from_ty(generics, sig.0.output, variance);
     }
 
     /// Adds constraints appropriate for a region appearing in a
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index ce1ad1dddc8..bfb50bcbc25 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -1176,15 +1176,6 @@ impl Clean<FnDecl> for hir::FnDecl {
     }
 }
 
-impl<'tcx> Clean<Type> for ty::FnOutput<'tcx> {
-    fn clean(&self, cx: &DocContext) -> Type {
-        match *self {
-            ty::FnConverging(ty) => ty.clean(cx),
-            ty::FnDiverging => Bottom
-        }
-    }
-}
-
 impl<'a, 'tcx> Clean<FnDecl> for (DefId, &'a ty::PolyFnSig<'tcx>) {
     fn clean(&self, cx: &DocContext) -> FnDecl {
         let (did, sig) = *self;
@@ -1254,7 +1245,6 @@ impl Clean<Argument> for hir::Arg {
 pub enum FunctionRetTy {
     Return(Type),
     DefaultReturn,
-    NoReturn
 }
 
 impl Clean<FunctionRetTy> for hir::FunctionRetTy {
@@ -1262,7 +1252,6 @@ impl Clean<FunctionRetTy> for hir::FunctionRetTy {
         match *self {
             hir::Return(ref typ) => Return(typ.clean(cx)),
             hir::DefaultReturn(..) => DefaultReturn,
-            hir::NoReturn(..) => NoReturn
         }
     }
 }
diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index 854ca57e855..ce0cfa56439 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -634,7 +634,6 @@ impl fmt::Display for clean::FunctionRetTy {
             clean::Return(clean::Tuple(ref tys)) if tys.is_empty() => Ok(()),
             clean::Return(ref ty) => write!(f, " -&gt; {}", ty),
             clean::DefaultReturn => Ok(()),
-            clean::NoReturn => write!(f, " -&gt; !")
         }
     }
 }
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 6ba5eccc5cf..9046a44fdc6 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -1567,9 +1567,6 @@ impl fmt::Debug for ImplPolarity {
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum FunctionRetTy {
-    /// Functions with return type `!`that always
-    /// raise an error or exit (i.e. never return to the caller)
-    None(Span),
     /// Return type is not specified.
     ///
     /// Functions default to `()` and
@@ -1583,7 +1580,6 @@ pub enum FunctionRetTy {
 impl FunctionRetTy {
     pub fn span(&self) -> Span {
         match *self {
-            FunctionRetTy::None(span) => span,
             FunctionRetTy::Default(span) => span,
             FunctionRetTy::Ty(ref ty) => ty.span,
         }
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index 47addd8aba5..6c5cbdc645a 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -638,7 +638,6 @@ pub fn noop_fold_fn_decl<T: Folder>(decl: P<FnDecl>, fld: &mut T) -> P<FnDecl> {
         output: match output {
             FunctionRetTy::Ty(ty) => FunctionRetTy::Ty(fld.fold_ty(ty)),
             FunctionRetTy::Default(span) => FunctionRetTy::Default(span),
-            FunctionRetTy::None(span) => FunctionRetTy::None(span),
         },
         variadic: variadic
     })
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 6214dc5301b..a5d512f14ec 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -2696,10 +2696,6 @@ impl<'a> State<'a> {
                 self.maybe_print_comment(ty.span.lo)
             }
             ast::FunctionRetTy::Default(..) => unreachable!(),
-            ast::FunctionRetTy::None(span) => {
-                try!(self.word_nbsp("!"));
-                self.maybe_print_comment(span.lo)
-            }
         }
     }
 
@@ -2955,8 +2951,6 @@ impl<'a> State<'a> {
         try!(self.ibox(INDENT_UNIT));
         try!(self.word_space("->"));
         match decl.output {
-            ast::FunctionRetTy::None(_) =>
-                try!(self.word_nbsp("!")),
             ast::FunctionRetTy::Default(..) => unreachable!(),
             ast::FunctionRetTy::Ty(ref ty) =>
                 try!(self.print_type(&ty))
diff --git a/src/test/run-pass/issue-10714.rs b/src/test/run-pass/issue-10714.rs
deleted file mode 100644
index 795ad8fb35b..00000000000
--- a/src/test/run-pass/issue-10714.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-// pretty-expanded FIXME #23616
-
-enum v {}
-pub fn main() {
-    let y: v = unsafe { ::std::mem::uninitialized() };
-}